What Is The Fat Burning Zone?

What Is the Fat-Burning Zone?

When it comes to exercise, particularly cardio exercise, there are different heart-rate zones that equate to different levels of intensity. These levels actually determine which energy systems your body uses during exercise, and that often directly affects how many calories you burn.

There are four different training zones and each is a percentage of your maximum heart rate (MHR), the maximum number of times your heart can beat in a minute:

Low intensity, also known as the "fat-burning zone," is 50% to 70% of your MHR. It's usually considered light cardio or a warm-up level.

Moderate intensity is 70% to 80% of your MHR. At this level, you'll be working out but still be able to talk. 

High intensity is 80% to 90% of your MHR. This usually puts you well out of your comfort zone and pushes you to your anaerobic threshold,  which is when your cardiovascular system can't deliver oxygen to your muscles fast enough. 

Maximum effort is 90% to 100% of your MHR, something that even the most highly trained athletes can't maintain for more than a few minutes.  

The Truth About Your Fat-Burning Zone

From these numbers, you can see that the fat-burning zone is the lowest intensity. So why is it called the fat-burning zone? Because the body relies on more stored fat (versus carbs) as its primary fuel source when you work at a lower intensity compared to a higher intensity.

Some people have translated this to mean that you actually burn more fat when you work at a lower intensity, but that's a bit of a misconception. In reality, picking up the pace will torch more total calories—and ultimately more fat—in less time. And it's the number of calories you burn overall that leads to the most weight (and fat) loss.

To give you an example, the chart below details both the total calories and the fat calories expended by a 130-pound woman during cardio exercise.

As you'll see, the woman burns more total calories and more fat calories when working out at a higher intensity.

	Low Intensity (60 percent to 65 percent MHR)	High Intensity (80 percent to 85 percent MHR)
Total calories expended per minute	4.86	6.86
Fat calories expended per minute	2.43	2.7
Total calories expended in 30 minutes	146	206
Total fat calories expended in 30 minutes	73	82
Percentage of fat calories burned	50%	39.85%

While lower-intensity workouts are great for beginners and for building endurance, you need to work harder during some workouts if you really want to burn fat and lose weight.

The Case for Low-Intensity Exercise

Now, this isn't to say that low-intensity exercise doesn't have its place, especially if you're just starting out and can't sustain a faster pace. If you go slower, you may be able to exercise a lot longer, so you'll end up burning more calories and fat that way. 

Even for more advanced exercisers, endurance workouts should be a staple of a complete fitness program along with shorter, higher-intensity workouts or interval workouts.  A type of training in which you alternate periods of high-intensity exercise with low-intensity recovery periods, intervals are proven to increase fitness and burn more calories than you would when doing the same thing during your whole workout.

Structuring Your Cardio Workouts

If you want to lose weight, a general cardio schedule would include workouts at a variety of intensities within your target heart rate zone.  If you're doing five cardio workouts a week, you might have one high-intensity workout, one lower-intensity workout, and three somewhere in the middle.

Sample Cardio Workout Program for Beginners

A beginner cardio program lets you slowly build endurance while getting you a bit out of your comfort zone. That way you don't have to spend an entire workout miserable, yet you'll still challenge yourself, which will burn more calories.

Below is a sample program that will help get you started. 

Day	Workout/Intensity	Length
Monday	Beginner-Interval Workout	Up to 21 minutes
Tuesday	Low-Intensity Walking	10 to 20 minutes
Wednesday	Rest
Thursday	Cardio-Endurance Workout	Up to 35 minutes
Friday	Rest
Saturday	Interval Training Level 2	Up to 25 minutes
Sunday	Low-Intensity Walking	10 to 20 minutes

The key is to start with what you can handle and slowly build from there. If you're just getting started, don't worry too much about how hard you're working. Focus more on making exercise a habit you can manage on a regular basis.

Exercise Changes You At A Molecular Level

Exercise is good for you, this we know. It helps build muscle, burn fat and make us all into happier, healthier people. But long before you start looking the way you want, there are other hidden, more immediate, molecular and immunological changes taking place inside your cells. Changes which could be responsible for protecting us from heart disease, high blood pressure, type 2 diabetes – and even steve off old age and cancer. 

You may think that “molecular” changes may not be that much of a big deal. Surely it is fat loss and muscle gain that are the best outcomes of exercise? Actually molecular changes affect the way genes and proteins are controlled inside cells. Genes can become more or less active, while proteins can be rapidly modified to function differently and carry out tasks such as moving glucose into cells more efficiently, or protect cells from harmful toxins.

Type 2 diabetes causes all kinds of health problems, including cardiovascular disease, high blood pressure, blindness, kidney failure and nerve damage, and may lead to limb amputation. The underlying cause is the development of a heightened inflammatory state in the body’s tissue and cells. This damages cells and can eventually lead to insulin resistance and, ultimately, type 2 diabetes.

The main risk factors for type 2 diabetes include obesity, a poor diet and a sedentary lifestyle. However, we have found that even low intensity exercise, such as brisk walking, can increase the body’s insulin sensitivity. This means that people at risk of developing diabetes become less prone because they are able to metabolize glucose more efficiently.

In our study, we asked 20 sedentary people who were at risk of developing diabetes to walk briskly for 45 minutes, three times a week, for eight weeks. Although there was no change in their weight, blood pressure or cholesterol level, on average each participant lost a significant six centimeters from their waist circumference. And, more importantly, there was a reduction in their diabetic risk.

Immune system benefits

Interestingly, there were also exercise-induced changes in the participants’ monocytes – an important immune cell that circulates in the bloodstream. This led to a reduction in the body’s inflammatory state, one of the main risks for type 2 diabetes.

When our body is under attack from foreign invaders such as microbes, immune cells such as monocytes change into “microbe-eating” macrophages. Their main function is to fight infection in our tissues and lungs. There are two main types of macrophages, M1 and M2. M1 macrophages are associated with pro-inflammatory responses and are necessary for aggressively fighting off infections. However, in obese people who do not exercise, these cells become active even in the absence of infection. This can lead to an unwanted, heightened inflammatory condition which may “trigger” diabetes.

On the other hand, M2 macrophages play a role in “switching-off” inflammation and are instrumental in "damping-down" the more aggressive M1s. So a healthy balance of M1 and M2 macrophages is crucial to maintain an optimal immune response for fighting infections – and it may help prevent the heightened inflammatory condition which comes from lack of exercise and obesity too.

Other studies have also shown that exercise has a beneficial impact on tissues’ immune cell function and can reduce unnecessary inflammation. Exercise training in obese individuals has been found to reduce the level of tissue inflammation specifically because there are less macrophage cells present in fat tissue.

In addition, researchers have found a significant link between exercise and the balance of M1 and M2 macrophages. It has been shown that acute exercise in obese rats resulted in a shift from the “aggressive” M1 macrophages to the more “passive” M2 – and that this reduction in the inflammatory state correlated with an improvement in insulin resistance.

Time to move

There is no definitive answer as to how much and what intensity of exercise is necessary to protect us from diabetes. Though some researchers have shown that while higher-intensity exercise improves overall fitness, there is little difference  between high and low-intensity exercise in improving insulin sensitivity.

However, a new study has found that all forms of aerobic exercise – in particular high-intensity interval training such as cycling and running – can effectively stop aging at the cellular level. The exercise caused cells to make more proteins for their energy-producing mitochondria and their protein-building ribosomes. Researchers also observed that these “molecular” changes occurring at the gene and protein levels happened very quickly after exercise and that the effects prevented damage to important proteins in the cells and improve the way in which insulin functions.

Although you might not see the changes you want immediately, even gentle exercise can make a big difference to the way the body’s cells behave. This means that exercise could have far-reaching health benefits for other inflammatory associated diseases and possibly protect us against aging and cancer too.

Why Do We Need Water Filters

Sediment Removal

Mechanical filters are used to remove leaves and other debris from water, along with dirt, silt and clay particles in water. Mechanical filters may be made from metal screens, fabric, ceramic or paper. These impurities, called sediment, can cause an unpleasant taste but aren't usually a health risk. Most home water filtration units use replaceable paper filters that screen out fine sediment.

Reducing Minerals

Iron and other minerals, such as calcium and manganese, are not hazardous to human health, but they can cause drinking water to taste metallic or just unpleasant. Iron or manganese can cause clothing stains on when wash water contains these elements, and they can even discolor porcelain and other dishes washed in the mineral-rich water. These minerals can build up in water pipes, gradually clogging them and reducing water pressure, possibly causing plumbing problems.

Pathogen Removal

Filtering water is essential to keep harmful bacteria and parasites from drinking water. Giardiasis is a type of illness that causes diarrhea and can last as long as six weeks. The microscopic parasite that causes the disease is Giardia intenstinalis, an organism that can survive in the environment for many months. It can be ingested from water that has become contaminated with animal or human feces. Another parasite that can cause similar symptoms is cryptosporidium. Cryptosporidium is resistant to chlorine and must be filtered out with mechanical filters. These pathogens are effectively removed by passing water through filters listed as micro-, ultra- and nano-filters.

Lowering Chlorine

Most municipal water utility companies use chlorine to treat drinking water because it's inexpensive, easy to use and highly effective at killing many of the bacteria found in water. It can also eliminate some viruses. While it's a good disinfectant, chlorine can make drinking water smell and taste unpleasant, and it can also react with some metals to form hazardous compounds. An activated carbon filter removes the chlorine smell and taste from water.

Removing Dangerous Lead

Lead is toxic when ingested, and it's essential to remove it from drinking water. Lead commonly gets into drinking water when it seeps into the water supply from old plumbing pipes or the solder used to join them together. It can be removed from water through reverse osmosis filters, distillation and carbon filters designed specifically to remove the metal. If you rely on well water, health agencies recommend that you have your well tested at least once a year for lead and other contaminants.

Pesticide and Chemical Removal

Before the 1940s most common pesticides contained heavy metals that did not readily dissolve in water, but today pesticide residue in drinking water may be on the rise because modern organic pesticides dissolve in water and can easily get into the water supply. Activated carbon filters can remove pesticides and volatile organic compounds from drinking water.

Benefits and Safety Tips For Stretching

1. Increases your flexibility

Regular stretching can help increase your flexibility, which is crucial for your overall health. Not only can improved flexibility help you to perform everyday activities with relative ease, but it can also help delay the reduced mobility that can come with aging.

2. Increases your range of motion

Being able to move a joint through its full range of motion gives you more freedom of movement. Stretching on a regular basis can help increase your range of motion.

One study found that both static and dynamic stretching are effective when it comes to increasing range of motion, although proprioceptive neuromuscular facilitation PNF - type stretching, where you stretch a muscle to its limit, may be more effective for immediate gains.

3. Improves your performance in physical activities

Performing dynamic stretches prior to physical activities has been shown to help prepare your muscles for the activity. It may also help improve your performance in an athletic event or exercise.

4. Increases blood flow to your muscles

Performing stretches on a regular basis may improve your circulation. Improved circulation increases blood flow to your muscles, which can shorten your recovery time and reduce muscle soreness (also known as delayed onset muscle soreness or DOMS).

5. Improves your posture

Muscle imbalances are common and can lead to poor posture. One study found that a combination of strengthening and stretching specific muscle groups can reduce musculoskeletal pain and encourage proper alignment. That, in turn, may help improve your posture.

6. Helps to heal and prevent back pain

Tight muscles can lead to a decrease in your range of motion. When this happens, you increase the likelihood of straining the muscles in your back. Stretching can help heal an existing back injury by stretching the muscles.

A regular stretching routine can also help prevent future back pain by strengthening your back muscles and reducing your risk for muscle strain.

7. Is great for stress relief

When you’re experiencing stress, there’s a good chance your muscles are tense. That’s because your muscles tend to tighten up in response to physical and emotional stress. Focus on areas of your body where you tend to hold your stress, such as your neck, shoulders, and upper back.

8. Can calm your mind

Participating in a regular stretching program not only helps increase your flexibility, but it can also calm your mind. While you stretch, focus on mindfulness and meditation exercises, which give your mind a mental break.

9. Helps decrease tension headaches

Tension and stress headaches can interfere with your daily life. In addition to a proper diet, adequate hydration, and plenty of rest, stretching may help reduce the tension you feel from headaches.

Stretching techniques

There are several types of stretching techniques, including:

• dynamic

• static

• ballistic

• PNF

• passive

• active stretching

The most common forms of stretches are static and dynamic:

• Static stretches involve holding a stretch in a comfortable position for a period of time, typically between 10 and 30 seconds. This form of stretching is most beneficial after you exercise.

• Dynamic stretches are active movements that cause your muscles to stretch, but the stretch is not held in the end position. These stretches are usually done before exercise to get your muscles ready for movement.

Tips

• Use dynamic stretches before exercise to prepare your muscles.

• Use static stretches after exercise to reduce your risk for injury.

How to start a stretching routine

If you’re new to a regular stretching routine, take it slow. Just like other forms of physical activity, your body needs time to get used to the stretches you’re performing.

You also need a solid grasp of proper form and technique. Otherwise, you risk getting injured.

You can stretch any time during the day. On days you exercise:

• aim for 5 to 10 minutes of dynamic stretching prior to your activity

• do another 5 to 10 minutes of static or PNF stretching after your workout

On days when you aren’t exercising, still plan to schedule at least 5 to 10 minutes of time for stretching. This can help improve flexibility and reduce muscle tightness and pain.

When stretching, focus on the major areas of your body that help with mobility, such as your calves, hamstrings, hip flexors, and quadriceps. For upper-body relief, try moves that stretch the shoulders, neck, and lower back.

Hold each stretch for 30 seconds and avoid bouncing.

You can stretch after each workout or athletic event, or daily after your muscles are warmed up. 

Risks and safety tips

Stretching may not always be safe:

• If you have an acute or existing injury, only perform stretches recommended by your doctor.

• If you have a chronic or nagging injury, consider talking with a sports medicine specialist or physical therapist to design a stretching protocol that fits your needs.

• If you have any physical limitations that prevent you from properly performing a stretching exercise, consult your doctor for alternative exercises that can help increase your flexibility.

Regardless of your fitness level, there are a few standard safety tips for stretching that you should follow:

• Don’t bounce. Years ago, ballistic stretching was thought to be the best way to increase flexibility. Now, experts suggest you avoid bouncing unless these types of stretches have been recommended to you by a doctor or physical therapist.

• Don’t stretch beyond the point of comfort. While it’s normal to feel some tension when stretching a muscle, you should never feel pain. If the area you are stretching starts to hurt, back off the stretch until you don’t feel any discomfort.

• Don’t overdo it. Like other forms of exercise, stretching puts stress on your body. 

If you’re stretching the same muscle groups multiple times a day, you risk over-stretching and causing damage.

• Don’t go into your stretches cold. Cold muscles are not as pliable, which makes stretching a lot more difficult. The best time to stretch is after you work out, but if you’re not exercising before performing your stretches, consider warming up for 5 to 10 minutes with some light cardio, such as walking or jogging.

The takeaway:

Whether you're new to exercise or a seasoned athlete, you can benefit from a regular stretching routine.  By incorporating 5 to 10 minutes of dynamic and static stretches into your daily workout, you can increase your range of motion, improve posture, and ease your mind. 

How To Get Started On A Plant Based Diet

Plant-based or plant-forward eating patterns focus on foods primarily from plants. This includes not only fruits and vegetables, but also nuts, seeds, oils, whole grains, legumes, and beans. It doesn’t mean that you are vegetarian or vegan and never eat meat or dairy. Rather, you are proportionately choosing more of your foods from plant sources.

Mediterranean and vegetarian diets

What is the evidence that plant-based eating patterns are healthy? Much nutrition research has examined plant-based eating patterns such as the Mediterranean diet and a vegetarian diet. The Mediterranean diet has a foundation of plant-based foods; it also includes fish, poultry, eggs, cheese, and yogurt a few times a week, with meats and sweets less often.

The Mediterranean diet has been shown in both large population studies and randomized clinical trials to reduce risk of heart disease, metabolic syndrome, diabetes, certain cancers (specifically colon, breast, and prostate cancer), depression, and in older adults, a decreased risk of frailty, along with better mental and physical function.

Vegetarian diets have also been shown to support health, including a lower risk of developing coronary heart disease, high blood pressure, diabetes, and increased longevity.

Plant-based diets offer all the necessary protein, fats, carbohydrates, vitamins, and minerals for optimal health, and are often higher in fiber and phytonutrients. However, some vegans may need to add a supplement (specifically vitamin B12) to ensure they receive all the nutrients required.

Vegetarian diet variety

Vegetarian diets come in lots of shapes and sizes, and you should choose the version that works best for you.

• Semi-vegetarian or flexitarian includes eggs, dairy foods, and occasionally meat, poultry, fish, and seafood.

• Pescatarian includes eggs, dairy foods, fish, and seafood, but no meat or poultry.

• Vegetarian (sometimes referred to as lacto-ovo vegetarian) includes eggs and dairy foods, but no meat, poultry, fish, or seafood.

• Vegan includes no animal foods.

8 ways to get started with a plant-based diet

Here are some tips to help you get started on a plant-based diet.

1. Eat lots of vegetables. Fill half your plate with vegetables at lunch and dinner. Make sure you include plenty of colors in choosing your vegetables. Enjoy vegetables as a snack with hummus, salsa, or guacamole.

2. Change the way you think about meat. Have smaller amounts. Use it as a garnish instead of a centerpiece.

3. Choose good fats. Fats in olive oil, olives, nuts and nut butters, seeds, and avocados are particularly healthy choices.

4. Cook a vegetarian meal at least one night a week. Build these meals around beans, whole grains, and vegetables.

5. Include whole grains for breakfast. Start with oatmeal, quinoa, buckwheat, or barley. Then add some nuts or seeds along with fresh fruit.

6. Go for greens. Try a variety of green leafy vegetables such as kale, collards, Swiss chard, spinach, and other greens each day. Steam, grill, braise, or stir-fry to preserve their flavor and nutrients.

7. Build a meal around a salad. Fill a bowl with salad greens such as romaine, spinach, Bibb, or red leafy greens. Add an assortment of other vegetables along with fresh herbs, beans, peas, or tofu.

8. Eat fruit for dessert. A ripe, juicy peach, a refreshing slice of watermelon, or a crisp apple will satisfy your craving for a sweet bite after a meal.

Inspiration for plant-based eating throughout the day.

Over time, eating a plant-based diet will become second nature. Here are some ideas to get you started.

Breakfast:

• Rolled oats with walnuts, banana, and a sprinkle of cinnamon.

• Breakfast wrap: Fill a whole-wheat tortilla with scrambled egg, black beans, peppers, onions, Monterey jack cheese, and a splash of hot sauce or salsa.

• Whole-wheat English muffin topped with fresh tomato and avocado slices, and blueberries.

Lunch:

• Greek salad: Chopped mixed greens with fresh tomato, Kalamata olives, fresh parsley, crumbled feta cheese, extra virgin olive oil, and balsamic vinegar. Whole-wheat pita on the side, fresh melon for dessert.

• Tomato basil soup, whole-grain crackers with tabbouleh, and an apple.

• Vegetarian pizza topped with mozzarella cheese, tomatoes, broccoli, onions, peppers, and mushroom. Fresh strawberries for dessert.

Dinner:

• Grilled vegetable kabobs with grilled tofu, and a quinoa and spinach salad.

• Whole-wheat pasta with cannellini beans and peas, and a romaine salad with cherry tomatoes, dressed with extra virgin olive oil and balsamic vinegar.

• Vegetarian chili with a spinach-orzo salad.

Healthy Morning Habits

Developing healthy habits is on everyone’s agenda but following through with our good intentions is harder than it seems, especially when you’re busy. The good news is that the less time intensive and complicated a habit is, the more likely we are to stick to it. Research shows that people maintain healthy habits when these are small and manageable changes to one’s lifestyle.

1. Stretch

Our feline friends do it naturally after waking up from slumber but the practice isn’t common enough in humans, which is a shame! A simple stretch in the morning can  improve  your posture,  reduce chronic back pain, increase blood flow to your brain for better focus, and energize you all at once. Plus, stretching right after you roll out of bed gives you time to reconnect to yourself and wake up gently.

Experts from the American College of Sports Medicine suggest focusing on hamstrings, hip flexors, calves and chest muscles as these are the most commonly tight and stiff muscles. Hold each stretch 15 to 30 seconds and repeat 3 to 5 times on each side of your body. As a rule of thumb, you should feel a slight pull, being careful not to stretch to a painful point.

If starting a stretching routine sounds intimidating, don’t fret! The key is to do what feels right to you. Less than five minutes is more than enough to start reaping benefits from working on your flexibility every day.

2. Have a Cup of Tea

Whether you enjoy green tea, a classic English Breakfast tea, or the trendy chai, forming the habit of having a cup every morning is a good idea. Packed with antioxidants named Epigallocatechin-3-gallate (EGCG) or catechins, tea leaves hold healing power. They fight free-radicals in our bodies to relieve inflammation, prevent diseases such as cancer, heart disease, and neurological decline.

Drinking tea as part of your morning rituals is also a good way to wake up gently as it promotes mental alertness without giving you a headache later on. Tea helps with digestive issues as well, and will get things moving so you can start your day feeling light and energized.

3. Get Some Sunshine

Getting a good dose of sunshine right when you wake up — whether by going outside for a short walk or having breakfast in a room with an east-facing window — is one of the easiest and most rewarding morning habits to get into.

Natural light is beneficial to regulate our circadian rhythms especially in the morning hours. It promotes wakefulness by stimulating the neurotransmitters involved with arousal in our brain. Exposure to light is also important to the production of melatonin an hormone essential to proper and restful sleep. How well you sleep at night can be determined as soon as you wake up!

4. Get Creative

Using our imagination and taking the time for creative pursuits is not something most of us are eager to do when we’re fighting with the snooze button but research says that early mornings are actually the best time to give our brains a bit of a workout.

Think of it this way: the demands put upon us during our day require us to make choices, use our willpower, and exercise our focus, all of which are tiring and weaken our ability to be creative. Getting our creative juices flowing not long after we wake up is a good way to seize upon those brain sources before our energies are depleted.

It also turns out this time of day is when our prefrontal cortex is most active. This brain area is closely related to artistic creativity and divergent thinking, or finding new ideas to solve problems.

Instead of scrolling through social media in the morning, why not try stream-of-consciousness journaling or mindlessly doodling for a few minutes while eating breakfast?

5. Eat a Piece of Fruit

Want to have a strong immune system, fight inflammation, get restful sleep, be full of energy, and have good skin?  Consuming fruit on a daily basis can help with all of that!

As the most important meal of the day, breakfast is the perfect time to incorporate at least one of our ‘5 a day’, especially as research shows that our ability to make healthy food choices weakens as the day goes on. Eating a good breakfast with the inclusion of at least one piece of fruit is an easy way to make sure that you get the necessary nutrients and antioxidants your body needs to thrive.

6. Add Chia Seeds to Your Breakfast

These seeds may be tiny, but their health benefits are not. Packed with omega-3s, fiber, a ton of micronutrients (potassium, calcium, iron, phosphorus and manganese), and antioxidants, chia seeds are good for digestion, regulating blood glucose, and preventing major diseases.

7. Take Your Vitamin B12

Whether you eat a plant-based diet or not, supplementing with vitamin B12 is a good idea. Far from being a vegan issue, it is estimated that up to 30% of the population is deficient in this vitamin.

Essential for maintaining the insulation of our nerve cells to protect our neurological and cognitive functions, vitamin B12 is also responsible for breaking down amino acids and fatty acids to supply our bodies with energy.

While You Are Sleeping

Sleep is essential for good health. In fact, we need sleep to survive — just like we need food and water. So, it’s no wonder that we spend about one-third of our lives sleeping.

Many biological processes happen during sleep:

- The brain stores new information and gets rid of toxic waste.

- Nerve cells communicate and reorganize, which supports healthy brain function.

- The body repairs cells, restores energy, and releases molecules like hormones and proteins.

These processes are critical for overall health. Without them, your body can’t function correctly.

Let’s take a closer look at why you sleep, along with what happens if you don’t get enough.

Why do you need to sleep?

A lot is still unknown about the purpose of sleep. However, it’s widely accepted that there isn’t just one explanation for why we need to sleep. It’s likely necessary for many biological reasons.

To date, scientists have found that sleep helps the body in several ways. The most prominent theories and reasons are outlined below.

Energy conservation

According to the energy conservation theory, we need sleep to save energy. This concept is backed by the way our metabolic rate drops during sleep.

It’s also said this happens because the body needs less energy at night, when it’s inconvenient to find food.

Cellular restoration

Another theory, called the restorative theory, says the body needs sleep to restore itself.

The idea is that sleep allows cells to repair and regrow. This is supported by many important processes that happen during sleep, including:

- muscle repair

- protein synthesis

- tissue growth

- hormone release

Brain function

The brain plasticity theory, says sleep is required for brain function. Specifically, it allows your neurons, or nerve cells, to reorganize.

When you sleep, your brain’s glymphatic (waste clearance) system clears out waste from the central nervous system. It removes toxic byproducts from your brain, which build up throughout the day. This allows your brain to work well when you wake up.

Sleep affects many aspects of brain function, including:

- learning

- memory

- problem solving skills

- creativity

- decision-making

- focus

-       concentration

Emotional well-being

Similarly, sleep is necessary for emotional health. During sleep, brain activity increases in areas that regulate emotions, including the:

- striatum

- amygdala

- hyppocampus

- insula

- medial prefrontal cortex

This change in activity supports proper brain function and emotional stability.

For example, the amygdala is in charge of the fear response. It’s what controls your reaction when you face a perceived threat, like a stressful situation.

When you get enough sleep, the amygdala can respond in a more adaptive way. But if you’re sleep deprived, the amygdala is more likely to overreact.

Weight maintenance

Sleep affects your weight by controlling hunger hormoes. This includes ghrelin, which increases appetite, and leptin, which increases satiety.

During sleep, ghrelin decreases because you’re using less energy than when you’re awake.

Lack of sleep, however, elevates ghrelin and suppresses leptin. This imbalance makes you hungrier, which may increase the risk of weight gain.

Proper insulin function

Insulin is a hormone that helps your cells use glucose for energy. But in insulin reistance, your cells don’t respond properly to insulin. This can lead to high blood glucose levels and, eventually, type 2 diabetes.

Sleep may protect against insulin resistance. It keeps your cells healthy so they can easily take up glucose.

The brain also uses less glucose during sleep, which helps the body regulate overall blood glucose.

Immunity

A healthy and strong immune system depends on sleep.

When you sleep, your body makes cytokines, which are proteins that fight infection and inflammation. It also produces certain antibodies and immune cells. Together, these molecules prevent sickness by destroying harmful germs.

That’s why sleep is so important when you’re sick or stressed. During these times, the body needs even more immune cells and proteins.

Heart health

While the exact causes aren’t clear, scientists think sleep supports heart health. This stems from the link between heart disease and poor sleep.

Lack of sleep is associated with risk factors for heart disease, including:

- increased sympathetic nervous system activity

- high blood pressure

- increased inflammation

- elevated cortisol levels 

- weight gain

- insulin resistance

What happens when you sleep?

Your body cycles through four stages of sleep. The pattern typically repeats every 90 minutes. This means the stages will repeat about 4 to 6 times during a 7- to 9- hour sleep period.

The pattern includes three phases of non-rapid eye movement (NREM) sleep and one phase of REM sleep.

The NREM sleep stages used to be divided into stages 1, 2, 3, and 4, followed by REM sleep. The National Sleep Foundation now classifies them as follows:

N1 non-REM sleep (formerly stage 1)

Stage 1 occurs when you first fall asleep. As your body enters light sleep, your brain waves, heart rate, and eye movements slow down.

This phase lasts for about 7 minutes.

N2 non-REM sleep (formerly stage 2)

This stage involves the light sleep just before deep sleep.

Your body temperature decreases, your eye movements stop, and your heart rate and muscles continue to relax. Your brain waves briefly spike then slow down.

During a night of sleep, you spend the most time in stage 2.

N3 non-REM sleep (formerly stages 3 and 4)

In stages 3 and 4, deep sleep begins. Your eyes and muscles don’t move, and your brain waves slow down even further.

Deep sleep is restorative. Your body replenishes its energy and repairs cells, tissues, and muscles. You need this phase to feel awake and refreshed the next day.

REM sleep

This stage first happens about 90 minutes after you fall asleep. It can last for about an hour.

In REM sleep, your brain waves and eye movements increase. Your heart rate and breathing also speed up.

Dreaming often happens during REM sleep. Your brain also processes information during this stage, making it important for learning and memory.

How much sleep do you need?

The recommended amount of sleep depends on your age. It also varies from person to person, but the National Sleep Foundation suggests the following durations:

- Birth to 3 months: 14 to 17 hours

- 4 to 11 months: 12 to 15 hours

- 1 to 2 years: 11 to 14 hours

- 3 to 5 years: 10 to 13 hours

- 6 to 13 years: 9 to 11 hours

- 14 to 17 years: 8 to 10 hours

- 18 to 64 years: 7 to 9 hours

- 65 years and older: 7 to 8 hours

What happens if you don’t get enough sleep?

Without enough sleep, your body has a hard time functioning properly.

Possible consequences of sleep deprivation include:

- mood swings

- anxiety

- depression

- poor memory

- poor focus and concentration

- poor motor function

- fatigue

- weakened immune system 

- weight gain

- high blood pressure

- insulin resistance

- chronic diseases (like diabetes and heart disease)

- early mortality

The bottom line

Sleep keeps us healthy and functioning well. It lets your body and brain repair, restore, and reenergize.

If you don’t get enough sleep, you might experience side effects like poor memory and focus, weakened immunity, and mood swings.

Most adults need 7 to 9 hours of sleep each night. If you’re having trouble sleeping, talk to a doctor or sleep specialist. They can determine the underlying cause and help improve the quality of your sleep.