The link between sleep deprivation, weight gain, and cortisol.

 The link between sleep deprivation,  weight gain,  and cortisol. 

If you work overnight shifts,  or experience sleep deprivation, this is for you. 

The Vicious Cycle: How Sleep Deprivation, Cortisol, and Weight Gain Are Linked

In our fast-paced, 24/7 world, sleep is often the first thing to be sacrificed. We burn the midnight oil to meet deadlines, binge-watch a new series, or simply try to cram more into our day. However, this seemingly harmless habit of skimping on sleep can have profound consequences for our health, particularly when it comes to our waistline. The relationship between sleep deprivation, the stress hormone cortisol, and weight gain is a complex and interconnected cycle that can be incredibly difficult to break.

The Role of Cortisol: Our Body's Alarm System

Cortisol is often referred to as the "stress hormone." It's a glucocorticoid produced by the adrenal glands and plays a crucial role in the body's stress response. When we face a threat—whether it's a physical danger or a mental stressor like a looming deadline—our body goes into "fight or flight" mode. Cortisol levels rise, increasing blood sugar to provide energy, and suppressing non-essential functions to help us deal with the perceived threat.

In a healthy system, cortisol levels are highest in the morning to help us wake up and start the day, and they gradually decrease throughout the day, reaching their lowest point at night to help us fall asleep. However, chronic stress and, as we'll see, a lack of sleep, can disrupt this natural rhythm.

Sleep Deprivation: A Stressor in Itself

When we don't get enough sleep, our body interprets this as a form of stress. The sympathetic nervous system, responsible for the "fight or flight" response, becomes activated, and this, in turn, signals the adrenal glands to produce more cortisol. A single night of poor sleep can cause a temporary spike, but chronic sleep deprivation leads to consistently elevated cortisol levels, particularly in the evening, which can make it harder to fall asleep later on [1].

This constant state of high alert has a ripple effect on our body's metabolism and appetite. High cortisol levels can lead to insulin resistance, making it harder for our cells to absorb glucose from the bloodstream. The body then stores this excess glucose as fat, particularly in the abdominal area [2]. This is why a "stress belly" is a real phenomenon and not just an old wives' tale.

The Impact on Hunger Hormones

Beyond its direct effect on fat storage, sleep deprivation also wreaks havoc on the hormones that regulate our appetite: ghrelin and leptin.

• Ghrelin: Often called the "hunger hormone," ghrelin signals to our brain that it's time to eat. When we are sleep-deprived, our body produces more ghrelin, making us feel hungrier [3].

• Leptin: Known as the "satiety hormone," leptin tells our brain that we are full and should stop eating. A lack of sleep decreases leptin levels, meaning we don't feel as satisfied after a meal [3].

The combination of increased ghrelin and decreased leptin is a recipe for overeating and poor food choices. The elevated cortisol levels further compound this problem, as they often lead to cravings for high-calorie, high-fat, and sugary "comfort" foods. This is our body's attempt to quickly boost energy levels, but it ultimately contributes to more weight gain.

Breaking the Cycle

The relationship between sleep deprivation, cortisol, and weight gain is a self-perpetuating loop. A lack of sleep raises cortisol, which increases appetite and fat storage. This weight gain, in turn, can make it harder to get a good night's sleep, further elevating cortisol and continuing the cycle.

So, how can we break free? The answer lies in prioritizing sleep.

1. Establish a Sleep Schedule: Go to bed and wake up at the same time each day, even on weekends. This helps regulate your body's internal clock and cortisol rhythm.

2. Create a Relaxing Bedtime Routine: Winding down before bed is crucial. Avoid screens, dim the lights, and try activities like reading, meditation, or a warm bath.

3. Optimize Your Sleep Environment: Ensure your bedroom is cool, dark, and quiet.

4. Manage Stress: Incorporate stress-reduction techniques into your daily life, such as exercise, mindfulness, or deep breathing exercises.

Ultimately, viewing sleep as a non-negotiable pillar of health, just like diet and exercise, is the first step toward breaking this vicious cycle. By prioritizing rest, we can regulate our hormones, manage stress, and put an end to the complex interplay that leads to unwanted weight gain.

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References

1. Leproult, R., Copinschi, G., Buxton, P., & Van Cauter, E. (1997). Sleep loss results in an elevation of cortisol levels the next evening. Sleep, 20(10), 865-870.

2. Epel, E., Moyer, A., Martin, C., et al. (2000). The role of stress and cortisol in the development of the metabolic syndrome. The American Journal of Clinical Nutrition, 71(3), 743-747.

3. Spiegel, K., Tasali, E., Penev, P., & Van Cauter, E. (2004). Brief sleep restriction increases morning hunger and evening hunger in healthy young adults. The Lancet, 363(9413), 1146-1147.

Andrew A.  Golub