By: Jenna Damron, ACE, FST
Exercise and diet are often solely credited as the main vessels through which an individual reaches their goals in the gym. 99% of all clients we see on a daily basis have 2 basic goals: fat loss and muscle gain. While diet and exercise are largely important in obtaining these goals, there is one often-overlooked factor that may be hindering you from reaching your goals: sleep. Sleep is the body’s natural reset button. It allows us to regroup, recharge, and recover from the physical, social, and psychological pressure we put on it on a daily basis. Sleeping affects the levels of many different hormones that can affect weight loss or muscle gain.
Leptin and Ghrelin are two hormones that can have a huge impact on your weight loss. Leptin acts as a long-term regulator of the body’s energy supply. This hormone suppresses hunger, and therefore induces weight loss. Ghrelin is produced in the lining of the stomach and the pancreas and on the other hand is a very fast acting hormone that plays a role in hunger and meal initiation. Ghrelin levels are highest right before a meal, and lowest right after a meal. A reduced sleep duration does not allow the body to reset these hormones and regulate them to normal, balanced levels, and therefore may lead to more ghrelin secretion, more eating and hunger, lower leptin levels and satiation, and therefore more weight gain.
Another important hormone that is largely affected by sleep is somatotropin, or human growth hormone. The importance of this hormone is dual-faceted. Growth hormone is produced and secreted by the pituitary gland. It is responsible for cell growth, reproduction and regeneration. During restful sleep, the pituitary gland secretes more somatotropin than it does during your wakeful hours. This means two things for your body. Adequate sleep and somatotropin levels help to repair muscles, which break down during exercise. This is important for those who want to gain muscle mass, but it is also important for those who want to lose weight. Muscle cells burns on average 5x more calories per hour than fat cells do. More muscle mass means more calories burned at rest, and a higher metabolism. Additionally, somatotropin directly affects your metabolism. A higher base metabolic rate means that you burn off the calories you eat at a higher rate, which translates into easier weight loss.
The last hormone that is affected by your sleep schedule is cortisol. Cortisol levels begin to rise approximately 2-3 hours after the onset of sleep, and continue to rise into early morning and early waking hours. Cortisol follows a wavelike pattern in conjunction with your sleep pattern. When your sleep cycle gets thrown off, your cortisol secretion cycle gets thrown off as well. For example, nighttime awakening is followed by a temporary inhibition in cortisol secretion. Cortisol is one of the many hormones that help to regulate the levels of glucose in the blood. It acts as the antagonist to insulin. Insulin stimulates muscle and fat tissue cells to absorb glucose out of the blood stream, while cortisol stimulates the body to conserve glucose in the bloodstream for potential use by vital organs like the brain and heart in stressful situations. Weight loss and gain is a very precarious balance between these two hormones. Prolonged levels of cortisol in the blood can lead to weight gain as unused glucose in the blood stream gets stored in fat cells. If the cortisol-insulin balance in your blood becomes irregular due to an irregular sleep cycle, it can make for a difficult time shedding fat and gaining muscle.
In conclusion, there are many different factors that could be affecting your ability to reach your fitness goals. While exercise and diet are the main and obvious contributors, it is important to realize the whole picture. Taking good care of your body through diet, exercise, proper hydration, and a solid 8 hours of sleep per night is the best way to keep your body healthy and achieve your goals in the gym.
Jenna-Leigh Damron is currently a senior at Arizona State University working on her degrees in Psychology and Exercise & Wellness. She is also a certified personal trainer through the American Council on Exercise. She says that her job as a personal training is the perfect combination of her love for the human body and her passion to help people better the quality of their lives. She also loves playing soccer and supporting her clients and watching them succeed.
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