Benefits of Intermittent Fasting and Medium Intensity Interval Exercises

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Intermittent fasting has increased in popularity over the past few years. It is known to have many benefits, such as reduced inflammation, weight loss, and improved balance of blood sugar.

But the question is, is there any link between intermittent fasting and thyroid health? Do they fit together? Can a hypothyroid patient practice intermittent fasting? What role do intermittent fasting and interval exercise play in weight loss in a hypothyroid individual? We’ll review these and more in this article.

WHAT IS HYPOTHYROIDISM?

An individual is said to experience hypothyroidism when his or her body fails to produce sufficient thyroid hormones.

Your thyroid provides energy to almost all the organs in your body. It regulates vital functions such as your heartbeat, the workings of your digestive system, and lots more. If thyroid hormone production is deficient in your body, your body’s functions will slow down.

Hypothyroidism is also known as an underactive thyroid. It is more common in women than in men. It affects mostly people over the age of 60, but then, younger people are not immune to it either, for it can start at any age. Hypothyroidism may be identified through its symptoms, or via a routine blood test.

The mild form of hypothyroidism is known as subclinical hypothyroidism. If you’ve been diagnosed with this condition, then you should know that it can be treated effectively. The treatment is also safe and simple.

Treatment for hypothyroidism relies on supplementing the deficient hormones with artificial hormones. The artificial hormones will replace the hormones that are deficient in your body and restore your body’s functions to their default physiological state.

What is there to know about intermittent fasting and interval exercise?

Now, if you scroll through any fitness/health publication or a social media platform, you’ll see one or two things about intermittent fasting and interval exercises. While intermittent fasting seems to be garnering a lot of attention, it is certainly not a new lifestyle.

There’s a lot of anecdotal reports and research about intermittent fasting and how to make it work – especially if you intend to combine it with exercise. If you are doing intermittent fasting and still want to exercise at intervals, there are a couple of pros and cons to consider before you decide to exercise in a fasted state.

Some studies have shown that combining fasting with exercise affects metabolism associated with insulin sensitivity, as well as muscle biochemistry. Several studies support exercising after eating (before digestion or absorption). This is very important for people with metabolic syndrome or type 2 diabetes.

A 2016 study by Bachman et al., found that an upside while fasting is that glycogen (stored carbohydrates) will be deleted, so you will burn a lot of fat to fuel your exercise/workout. But does burning more fat seem like a win? Well…to some extent…but there’s a downside to it as well.

When you exercise in a fasted state, your body will switch to muscle as its fuel source. It will use the protein in your muscle for fuel. What’s more? Your energy will decrease and you may not be able to work out as hard as you’d like to.

The summary of it all is your body’s store of calories and energy will be depleted, resulting in a slowing of your metabolism.

Metabolic Issues Related To Thyroid Function

Your thyroid produces three important hormones namely:

Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin

Thyroxine and triiodothyronine are produced in the thyroid gland using iodine and tyrosine. Iodine is a trace mineral while triiodothyronine is an amino acid.

There are four molecules of iodine in thyroxine, and three of it in triiodothyronine. It is also important to note that your body can make about 4 times the amount of thyroxine as triiodothyronine.

After thyroxine and triiodothyronine have been synthesized, they are released into the circulation (the bloodstream) by the thyroid gland. The release of T4 and T3 occurs in response to stimulation of the pituitary – a part of your brain that produces Thyroid Releasing Hormone (TRH).

Thyroid Releasing Hormone sends signals to your thyroid gland to secrete thyroid hormones into your general circulation. Thyroid hormones exert their effects on all the cells in your body to boost cellular metabolism or activity.

Excess of thyroid hormone or too little of it impacts your body’s metabolism. Calcitonin, on the other hand, is a hormone that affects the amount of phosphate and calcium in your blood. It stimulates the absorption of more calcium into your bone matrix.

The Link Between Hypothyroidism and Weight Gain

The thyroid gland plays an important role in most of your body’s daily functions, such as organ function, temperature control, and metabolism. These functions are impacted when your body fails to produce sufficient thyroid hormone.

The severer the hypothyroid condition, the greater your likelihood of gaining more weight.

It is important to note that the amount of weight gain isn’t so high, though. In many cases, it is usually between 5 and 10 pounds. If you undergo proper treatment, then you may lose whatever weight you gained when your thyroid levels were uncontrolled. But note that this is not always the case.

This is not to say that they’ve not been treated properly. Rather, it may mean that your weight gain was due to lifestyle choices and not deficient hormone levels.

After getting the necessary treatment(s), you may lose weight. Why is this so? Because the restoration of your thyroid levels equally restores your ability to manage your weight properly.

If there are no weight changes after treating hypothyroidism, it doesn’t mean that weight loss cannot be achieved.

With the help of a registered dietitian, a personal trainer, or a medical doctor, you can create a healthy eating plan and exercise regimen that can set you on the path to healthy weight loss.

Thyroid Hormones, Body Metabolism, and Weight

Thyroid hormones exert a great influence on body metabolism, appetite regulation, and body temperature. It is important to note that the thyroid works hand-in-hand with your hypothalamus to maintain your energy balance and your weight.

Scientists do not really know how this happens, but one thing is certain: the thyroid hormones alone do not determine the amount of energy used by your body. Thyroid hormones work together with other hormones, nuclear receptors, proteins, and chemicals, which makes it a very complex process.

Several studies examining the link between thyroid hormones and weight have yielded varying results. Most researches have shown that the following holds true regarding thyroid hormones in the obese population:

Thyroid-stimulating hormone levels (TSH) are normal to slightly elevated
Free triiodothyronine levels (T3) are high
Free thyroxine levels (T4) are low

Other studies have however reported that these hormones may be on the normal or low levels. A 2014 study examined 1,944 adults with healthy thyroids. The participants were followed for 11 years. The results from the research showed that an increase in TSH levels was associated with weight increase over time in both genders.

The researchers concluded that the relationship between weight gain and TSH does not mean that either causes the other. Rather, the researchers proposed that a third factor could be involved.

Losing weight is no easy task. In fact, it can be challenging especially for hypothyroid individuals. Researchers are not sure why this happens, but there are indications that hormone resistance and low T3 levels may contribute to this.

T3 is active at the cellular level. It delivers energy and oxygen to cells, and it is usually low in hypothyroid patients. Low T3 levels are associated with low resting metabolic rates.

It is important to note that more T4 is produced by the thyroid gland than T3. However, T4 is activated to T3 in body tissues. The metabolic effect of thyroid hormone comes from T3. It increases metabolism, stimulates weight loss, and produces energy.

It is also worth knowing that T4 can be converted to reverse T3 (rT3). Reverse T3 is an inactive form of T3 that inhibits the effects of T3. Your body’s energy requirements determine the balance of T3 and rT3 in your body.

RT3 is usually produced when the body is starving. The goal is to reduce metabolism. RT3 is also produced during stressful periods or when a person is dieting. Since rT3 is a product of T4, it is thought to play a role in thyroid disease. Investigations have been carried out but the results are unclear.

Low rT3 and T3 usually characterize hypothyroidism. But in some cases, the individual may develop a high rT3 level. This can trigger weight gain.

Intermittent Fasting And The Thyroid

Intermittent fasting is a pattern of eating that shifts between periods of eating and fasting. Intermittent fasting does not specify the kind of foods a person should eat.

It only focuses on when a person should eat those foods. From this perspective then, one can say that intermittent fasting isn’t the conventional diet, but an eating pattern.

This practice has roots in human evolution when access to food was unpredictable and periodic fasting was natural. Fasting is also practiced for spiritual reasons across many religions, including Christianity, Islam, Buddhism, Judaism, etc.

Fasting seems more natural and healthy than having three meals and snacks daily.

The Fasting Methods

Intermittent fasting includes various methods that alternate between fasting and eating periods throughout the week. During fasting periods, you can’t eat food, but you can drink water, unsweetened tea, or coffee. Here are some popular intermittent fasting methods:

Fast for 12 Hours a Day:
This method involves fasting daily for 12 hours, typically from 7 PM to 7 AM, including sleep. It’s easy for beginners to manage and is recommended for people with hypothyroidism and Hashimoto’s because it can help regulate blood sugar levels, improve insulin sensitivity, and support weight management.
Fasting for 16 Hours (16/8 Method):
The 16/8 method involves fasting for 16 hours and eating during an 8-hour window, such as eating between 12 PM and 8 PM and fasting from 8 PM to 12 PM the next day. This extended fasting helps with metabolism, reduces cholesterol and glucose levels, and provides significant health benefits. It can be beneficial for people with hypothyroidism and Hashimoto’s, but it should be done under medical supervision and with regular testing to avoid issues with thyroid hormone levels.
Fasting for 2 Days a Week (5:2 Diet):
In the 5:2 Diet, you usually eat for five days and restrict your calorie intake to 500-600 calories on the other two days, generally not consecutive, to allow the body time to recover. This method is not recommended for people with thyroid conditions because it can cause a slowdown in metabolism, exacerbating symptoms such as fatigue, weight gain, and difficulty losing weight. It can also cause fatigue and low energy levels.

By cutting down on the number of calories you take, you will be able to lose weight. However, you should avoid compensating by overeating during the non-fast periods.

Many people tend to be more comfortable with the 16/8 method as it seems to be the simplest, easiest, and most sustainable. It is also more popular than the rest.

What role does intermittent fasting have on the thyroid?

Fasting affects the thyroid. It also has a direct impact on metabolism and energy utilization by the body. It is important to note that there is usually a drop in thyroid hormone level during intermittent fasting.

Intermittent fasting also causes a drop in thyroid hormone (T3) level and an increase in reverse T3 (rT3) level. T3 is vital for energy utilization by the body, but when you are on a fast, your body will strive to conserve as much energy as it can as it has no clue when food will be eaten again.

The reduction in thyroid hormone (T3) levels is caused by a reduction in the rate at which T4 is converted to T3. Of course, the balance is restored once you begin feeding normally.

Fasting is beneficial – it appears that levothyroxine usually taken during the fast period has higher efficiency and better absorption rate compared to when it is taken during regular feeding days.

Intermittent Fasting and Hashimoto’s

It is important to note that a metabolic deficiency can cause problems with your immune system. Autoimmune disorders and allergies are a function of malfunctioning immune cells and a deregulated metabolism.

Bad stomach ache because of Lactose intolerance.

Intermittent fasting has anti-inflammatory effects – studies have shown that it exerts this effect for autoimmune conditions like multiple sclerosis. It also helps with flareups, indicating that it must occur before the condition progresses.

Intermittent fasting also plays a therapeutic role in rheumatoid arthritis – by reducing pain and inflammation. It helps with blood sugar regulation in Type 1 & 2 diabetes.

So, how do you start intermittent fasting with Hashimoto’s?

Well, it is important to note that people with thyroid issues should adopt a cautious approach towards implementing intermittent fasting into their lifestyle.

Consult your healthcare provider

Start slowly

You should begin your intermittent fasting regimen with short fast schedules or protocols, for instance, 12:12 or 14:8 hours.

If you switch from being a frequent and heavy eater to one who abstains from food for at least 16 hours a day, a lot of molecular mechanisms will be activated within your body, causing it to switch into starvation mode.

This mode alters thyroid hormone production, which may place you at risk of weight gain.

Know what you are eating

Adjusting your feeding habits can cause a drastic change in your gut microflora. Eat a healthy diet in the right serving sizes. Sugar promotes the growth of bad bacteria, so it is important that you take in very little of it. Eat dark chocolate if you’re having a sweet tooth.

Studies have shown that people who eat less than 50g of dark chocolate three times weekly at the most did not gain weight. What’s more? Dark chocolate has anti-inflammatory properties.

Taking foods that contain inflammatory properties is counterproductive for intermittent fasting because your body will spend a lot of time (an average of 12-16 hours) repairing any correlated damages that have occurred.

Exercise moderately

Watch out for food triggers

Are you experiencing food trigger flare-ups? Then try not to eat foods that contain wheat or dairy products. It is important to note that 7 in 10 Hashimoto patients have dairy or wheat problems.

If you eat foods that you’re allergic to during intermittent fasting, you’ll feel severely fatigued and unable to focus on your daily tasks.

Beware of thyrotoxicity

If you are doing the 16:8 fasting technique, then start gradually and work your way up. You can do this by increasing your fasting hours by 20 minutes daily, for five days weekly. Leave out two days or weekends without an increase. This way, you would have increased your fasting hours by 6.5 hours within a month.

It is important that you track your diet as well as your symptoms and observe how well your health will improve over time.

How it Affects your Hormones and your Cells

Anytime you fast, a lot of changes take place in your body, both at the cellular level and at the molecular level. For instance, the level of hormones in your body is adjusted to increase access to fat stored in your body.

Vital repair processes are also initiated by your body cells while gene expression will be changed. The following are some of the changes that take place when you fast:

Gene expression: There will be changes in the functions of genes associated with disease protection and longevity.
Cellular repair: Cellular repair processes are initiated by your cells during fasting.
Autophagy is one of these processes. Here, old and dysfunctional proteins accumulating inside cells are digested and flushed.
Insulin: There is an improvement in insulin sensitivity and a drastic reduction in insulin levels. Low insulin levels increase access to stored body fat.
Human Growth Hormone (HGH): HGH levels skyrocket by as much as 5-fold. This contributes to muscle gain and fat loss.
Influence’s leptin sensitivity: Leptin is an important hormone that greatly influences appetite. A drop in your leptin level will trigger feelings of hunger and is believed to contribute to weight loss plateaus.
Overweight or obese individuals have high leptin levels but are resistant to it. Conversely, lean individuals have low leptin levels but are very sensitive to it.
Extended fasting leads to a loss of body fat. When this happens, leptin production will decrease. Recall that leptin is produced in fat cells. This means that there will be a decrease in the amount of leptin circulating in the blood.
Studies have shown that leptin levels can fall very fast during fasting and one reason for this is a high appetite. Another study investigating the role of leptin in weight loss has found that the fall in leptin levels may cause overeating in some people.

Other changes that may take place include:

Lower triglyceride levels
Improve blood sugar
Restore the concentration of ghrelin (also known as the hunger hormone) to physiological levels (normal levels).

Interval Training

Interval training isn’t as complicated as you may think. It simply means alternating short bursts of intense activity (30 seconds) with extended intervals (1-2 minutes) of mild activity.

If you aren’t fit, you could alternate it with fast periods of walking. Let’s assume you are walking outdoors, you can increase your pace between trees, mailboxes, or other landmarks.

For people with hypothyroidism doing exercises in machines like bicycle or treadmill, you can set up into a medium speed for 60 seconds and then rest for 2 minutes (to mimic the high intensity 30 seconds and lower the speed for 90 seconds.

Effects of Exercising on Thyroid Hormone Levels

A 2006 study by Ciloglu et al., investigated the effects of acute aerobic exercise on thyroid hormone levels. The study involved 60 male well-trained athletes performing bicycle ergometers at low, medium, and high intensity (45%, 70%, and 90% respectively).

The parameters measured in these individuals included thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), total triiodothyronine (T3), free thyroxine (fT4), serum total thyroxine (T4), blood lactic acid, and heart rate.

Results obtained from the study showed that exercise performed at moderate intensity (the anaerobic threshold) (70%) caused very prominent changes in hormone values.

T4, FT4, and TSH rose at 90% of maximum heart rate, while T3 and fT3 began to fall, indicating that aerobic exercise influences the level of circulating thyroid hormones.

Why is interval Training Good for your Thyroid?

We’ve already reviewed the symptoms of hypothyroidism (underactive thyroid). Some of these symptoms include depression, heart palpitations, joint pain, and fatigue. We’ve also seen that hypothyroidism reduces metabolism, thus increasing one’s likelihood of weight gain.

It is important to note that interval training can relieve most of the symptoms associated with hypothyroidism, while also improving muscle mass and cardiovascular health.

Increase your heart rate

Engaging in activities like brisk walking, running, or a sport can greatly boost your cardiovascular health. What’s more? Interval training and exercise also have mood-uplifting benefits which relieve hypothyroid symptoms like fatigue and depression.

Protects the joints

Hypothyroid patients frequently experience joint and muscle pain. Low-impact exercises that reduce stress on the hip, knee, or back joints may be easier to do compared to strenuous activities. Examples include swimming, walking, biking, and yoga.

Muscle building

Studies estimate that for each pound of increase you have in muscle mass, there’s an accompanying increase in your resting metabolism by 30-50 calories. This is good news for people who seek to lose weight.

By burning 5 pounds of fat and replacing it with 5 pounds of muscle tissue, your metabolism goes up by 250 calories daily. With this, you can burn an extra 250 calories daily even while relaxing.

Note that losing 5 pounds of muscles due to inactivity or aging means that you’re burning fewer than 250 calories. These numbers are estimates considering that metabolic rates vary on an individual basis.

Other benefits of lifting weights include:

Improves body composition
Physical fitness
Increases bone density
Prevents injury

Studies have shown that obesity reduces an individual’s response to exercise. Obese people may find it harder to build skeletal muscle proteins. Why this is so isn’t fully understood, but the research points to underlying hormonal deficiencies, like hypothyroidism.

Conclusion

Being a hypothyroid patient does not mean that you can’t take part in exercise activities. However, a recent study has shown that even professional athletes may find it harder to engage in high-intensity exercises.

As such, hypothyroid patients have to adapt their exercise plans so that their bodies can recover from the effect. It is important to note that exercise cannot completely replace hormone therapy for the treatment of hypothyroidism.

Studies have shown that despite medications prescribed, hypothyroid patients may still feel some form of discomfort during exercise.

However, when practiced within safe limits (as in interval exercises), the hypothyroid individual may benefit immensely from the therapeutic effects of exercise. As such, you must discuss your goals and exercise plans with your healthcare provider before beginning a new regimen or routine.

The content on mythyroidrelief.com, such as text, videos, graphics or images, and other materials, are for educational and informational purposes only. It is not intended to be a substitute for professional medical and nutritional advice, diagnosis or treatment. It should not be used as a substitute for medical consultation. The knowledge provided in this blog comes from the author's own experiences and research. Consult your doctor before making any decisions about your medical care.

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