Why not sleeping makes us gain weight & other interesting facts

Why care about sleeping well? For starters, we spend around 1/3 of our entire lives sleeping. Sleep at least deserves some of our attention.

Sleeping is a key and significant aspect of our human experience. Taking for example the average age span in the United States being 78.79 years (data from 2019); then considering an average of 8 hours of sleep per night, that makes it about 211,788 hours that we spend asleep out of 635,363 hours of life. That is around 33% of our entire lives that we spend sleeping.

How much sleep do I need?

The average sleep an adult needs is 8 hours of sleep per night. Adults over 65 years & older need around 7.5 hours of shut-eye every day. Pregnant women need several more hours of sleep than the average adult.

Will the sleep I need change as I age?

Sleep patterns change as we age, as it is common for it to be harder to fall asleep and wake up often during the night. We tend to need less sleep as we age. For example, children in school-age (5-12 years old) need from 9 to 12 hours of sleep each night compared to the 7.5 hours in average a person over 65 years old needs.

What is the circadian rhythm?

A circadian rhythm consists of a 24 hour cycle that is ruled by our body´s internal clock, which in turn is regulated primarily by light exposure. We have many circadian rhythms that carry out essential functions, most importantly sleep and synchronized with our biological clocks.

What happens during sleep?

Sleep is a summation of many biological processes that occurs in phases and cycles which we will cover in another post. One of such processes is the brain storing new memories and getting rid of toxins. As we sleep, nerve cells or neurons reorganize as the body repairs damaged cells, and releases communicating molecules and proteins throughout the body.

Why can we gain weight if we are sleep deprived?

Our body is regulated by biological clocks, our nervous system, hormones and signalling molecules. One of such hormones is leptin. This hormone tells our body when to stop eating. Interestingly, when sleep deprived, less leptin is released and more ghrelin is secreted. What is ghrelin? Well, it helps to think about it this way: "Grr, grr" is the sound you imagine your stomach making when its hungry. Rather appropriately, ghrelin is the hormone that makes our body hungry. When sleep deprived, ghrelin outmatches leptin , and consequently we become more hungry and gain more weight. In addition, our metabolism becomes slower when we do not get enough sleep.

What is the role for sleep in muscle growth, recovery, and illness prevention?

Growth hormone is a signaling molecule secreted during sleep - a crucial hormone for muscle building. Most tissue and growth repair occurs during sleep. It makes sense then, that when we do weight lifting, small tears occur in our muscles, and these muscle cells among other cells are repaired during sleep with the aid of growth hormone.

When on a diet or building muscle, it is key we note that a large calorie deficit can lead to sleep problems. For example, starvation-level calorie restriction causes disturbances in our sleep, and sleep reduction in animals and humans alike.

Sleep is also important for the prevention of disease. Sleep deprivation increases pro-inflammatory processes by certain signaling molecules known as cytokines. These molecules are key in the communication & adequate functioning of our immune system.

If these were not enough reasons to take sleep more seriously and learn more about it. Lack of sleep can impair response time and even judgement. This can seriously hinder our ambitions and goals. Not only professionally, but also personally.

Kind regards,

Jorge A Cevallos, MD