This is the second instalment of my blog series that explores how hormones, chemical messengers that regulate your bodily functions, can affect your fitness.
In my previous blog, I explained the importance of cortisol, oestrogen, progesterone, and testosterone, which all play a critical role in promoting overall health and fitness.
In this blog, I will explain how other hormones—growth hormone, insulin, epinephrine, and norepinephrine—influence exercise and how you can manage their effects on your body.
Growth hormone is produced in the brain by the pituitary gland, which is responsible for the secretion and storage of hormones.
Growth hormone is released to some degree during any type of exercise. Its primary function is to stimulate muscle growth and repair after you tear muscle fibres—this makes them stronger and more resilient. Growth hormone does this by helping to build new muscle tissue, which will lead to increased muscle size and strength.
Growth hormone also plays a role in fat metabolism, the process that occurs when your body breaks down fat to use it for energy. It helps convert stored fat into fuel that your body needs during exercise, which can have an impact on overall performance.
How to manage it
Performing higher-intensity exercises, such as resistance training, sprinting, or interval training stimulates the release of growth hormone. In addition, it's important to get enough sleep, as this is when the majority of growth hormone is released, and maintain a good diet that is rich in protein, healthy fats, and complex carbohydrates.
Studies have shown that intermittent fasting (time-restricted eating) can also help increase growth hormone production, as extended periods of non-eating stimulate its release.
While there are several natural and simple ways to increase the production of growth hormones, synthetic supplements exist that may be illegally used to enhance athletic performance or build muscle mass (no they're not the same as steroids). The use of such supplements comes with a range of negative side effects, including excess hormone production, which can lead to gigantism, joint and muscle pain, and an increased risk of diabetes and cancer.
Insulin is produced by the pancreas and is responsible for regulating blood sugar levels in your body. When blood sugar levels rise, insulin is released into your bloodstream to help move glucose from the blood into cells where it can be used for energy or stored for later use.
During any exercise, your body demands more energy, which is when insulin levels usually decrease to allow the body to more efficiently use stored glucose (glycogen) in the muscles and liver. This decrease can lead to an increase in fat burning because the body is more likely to use stored fat as a source of energy.
Meanwhile, increased insulin production can be beneficial for athletes or those with performance goals that would benefit from an increase in the amount of glycogen stored in muscles, which can later be used to fuel intense exercise.
How to manage it
The relationship between insulin and exercise is complicated and can vary depending on several factors, such as exercise type and intensity.
The ways to increase or decrease insulin production are generally similar: eat a balanced diet that is low in processed foods and refined carbohydrates, manage stress levels and your weight, and exercise regularly. However, the types of exercise matter.
Types of exercise that may be effective at reducing insulin levels include high-intensity interval training, resistance training, and aerobic exercises, such as running, cycling, or swimming. Whereas types of exercise that may be effective at increasing insulin levels include endurance exercise and interval training with shorter rest periods.
Individuals with medical conditions may not be able to naturally manage their insulin levels. Those with type 1 diabetes may not be able to naturally increase insulin production and may require insulin injections to avoid hyperglycaemia (high blood sugar levels). For those with type 2 diabetes, the primary issue is insulin resistance and not an excess of insulin production. They do not typically need injections but are encouraged to make lifestyle changes or take medication to improve insulin sensitivity and manage blood sugar levels.
Epinephrine and norepinephrine
Epinephrine and norepinephrine, also known as adrenaline and noradrenaline, are released during exercise in response to the body's increased demand for energy. They are part of your body's fight or flight response to stress or danger.
These hormones can have several positive effects on your body during exercise. They can stimulate the heart to beat faster, which increases blood flow to the muscles. They can increase blood pressure to help maintain blood flow to your muscles. They can stimulate your respiratory system, which increases your breathing rate and volume. And finally, they can increase glucose release from the liver into the bloodstream, which provides the body with more energy.
However, when the body is exposed to high levels of stress, such as during very strenuous exercise, it can release too much epinephrine and norepinephrine, which can have a range of negative effects on the body. These effects include increased anxiety, heart palpitations (fast or irregular heartbeats), and decreased insulin sensitivity, which could lead to conditions like type 2 diabetes.
How to manage it
In general, any exercises that place a high demand on the body's cardiovascular system or muscles can increase the release of epinephrine and norepinephrine. This includes high-intensity interval training, heavy resistance training, plyometric exercises, and high-intensity team sports, such as basketball or hockey.
On the other hand, most types of low-to-moderate-intensity exercises, such as brisk walking, cycling, or swimming, as well as mind-body exercises like yoga and tai chi can help decrease epinephrine and norepinephrine levels in the body. These exercises generally demand less energy from the body, which avoids triggering the body's stress response.
Regular exercise equals better hormonal balance
As I said in my previous blog, it's clear that hormones play a crucial role in overall health and fitness. Put simply, regular exercise can help improve hormonal balance, however, understanding the different hormones that affect your body during exercise will help you to optimise your workouts and help achieve your fitness goals faster.
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