Sleep, Weight and Our Immune System

The Guinness Book of World Records find it acceptable for a man (Felix Baumgartner) to ascend 128,000 feet into the outer reaches of our atmosphere in a hot-air balloon wearing a spacesuit, open the door of his capsule, stand atop a ladder suspended above the planet, and then free-fall back down to earth at a top speed of 843mph (1,358kmh), passing through the sound barrier while creating a sonic boom with just his body (Walker 2017 p. 133). Yet, this same Guinness Book of World Records will no longer accept any challenge to sleep deprivation as the health risks associated with it are considered far greater. With that in mind, as we enter the festive season, you might want to take a minute to think about sleep.

Any less than 7 to 8 hours of sleep each night leads to malfunctioning of many parts of our brain, contributing to depressed immune systems, neurological and psychiatric disorders as well as affecting every physiological system of the body. There are direct associations to immune deficiency, Alzheimer’s, anxiety, depression, bipolar disorder, suicide, stroke, chronic pain, cancer, diabetes, heart attacks, infertility, weight gain and obesity.

Sleep plays an important role in a well-functioning immune system. It improves our T cell function which are our pathogen fighting heroes – they fight against virus infected cells, including COVID-19 infected cells. Sleep improves the ability of T cells to stick to the infected cells better and to destroy them.

How does sleep affect weight? With just 5 to 6 hours of sleep a night (compared to 7 to 8 hours), there is a significant increase in ghrelin and a material decrease in leptin, meaning you have much more of the “I’m hungry” hormone and much less of the “I’m full” hormone. In addition, there is an impact on the types of food you crave with a marked increase in sweet and heavy carbohydrate loaded foods. 

A lack of sleep can make you feel hungry and binge-eat.

If you struggle to have a good night’s sleep, here are some useful pointers:

  • Have a sleep schedule – go to bed and wake up at the same time each day. If you struggle to go to bed at the same time, set an alarm for your bed time.
  • Exercise can help – try for a minimum of 30 minutes on each day but not later than 2 to 3 hours before bed.
  • Avoid/ reduce caffeine intake –stimulants can make it difficult for you to fall asleep. Nicotine is also a stimulant often causing smokers to sleep only lightly and can wake them up early in the morning due to nicotine withdrawal.
  • Alcohol can help you relax, however robs you of Rapid-Eye Movement (REM) sleep, keeping you in the lighter stages of sleep and can wake you up in the middle of the night when the effects of alcohol have worn off.
  • Common medications can disrupt sleep – including some heart, blood pressure, asthma medications as well as herbal remedies for colds and allergies – chat to your GP about your medication if this concerns you.
  • Have a relaxing ritual before bed to unwind – read a book, listen to music etc.
  • Have a dark, cool & gadget–free bedroom.
  • Natural sunlight regulates daily sleep patterns – try to get outside for 30 minutes each day.

If you like to read, Why We Sleep by Matthew Walker PhD – professor of Neuroscience and Psychology at UC Berkeley, should be next on your list. It is an evidence-based, fascinating, albeit quite confronting read about sleep and how important it is for our health.

Jen Hoult,
Accredited Practising Dietitian

Walker, M (2017) Why We Sleep. Unlocking the Power of Sleep and Dreams. Scribner, New York.