If you’re like a lot of my clients you’ll be working late, going to bed late, getting up early, training and repeating this cycle on an ongoing basis running on 6 hours or less sleep per night.

Whilst this routine might be sustainable for some, your training and body composition will suffer.

If you’re wanting to increase muscle mass and lose body fat, increasing your sleep length and quality is a must.

In a weight loss sleep study, subjects had 14 days of moderate caloric restriction with either 8.5 or 5.5 hours of sleep. Loss of fat and fat free mass was examined along with energy expenditure, hunger and metabolic hormone concentrations. The results showed that those in the 5.5 hours of sleep group showed a reduction of fat loss by 55% and increased their loss of fat free mass ie muscle by 60%. The sleep deprivation group also showed adaptation to calorie restriction, increased hunger and less utilization of body fat.

The conclusion of the study was that lack of sufficient sleep may compromise the effect of typical dietary interventions for weight loss.

Forced decreased sleep duration in healthy individuals has been linked to impaired glucose disposal. Poor or short sleep is also associated with pre-diabetic impairments such as elevated glucose and insulin, HBA1c or whole-body insulin resistance. Sleep loss also affects appetite and food intake. Studies have shown that subjects following sleep deprivation increase caloric intake by up to 20%.

For those of us in the 30-40 age bracket, growth hormone secretion over a 24 hour period decreases 2-3 times during this age period. The phase of sleep that we normally receive a large portion of our growth hormone pulse is during the first phase of sleep. If the beginning of our sleep is impaired then we can potentially miss out on out on our growth hormone pulse.

Training performance also decreases as a result of lack of sleep. Research has shown that those who sleep on average less than 8 hours per night increase their risk of injury during training by 1.7 times.

Cortisol levels are also increased as a result of sleep deprivation. One study took three groups. One group sleeping 11pm to 7am. The second group sleeping 4am to 8am and the third group did not sleep. After one night of sleep deprivation the 4am to 8am group had cortisol levels increase by 37% and the non-sleep group cortisol levels increased by 45%. The summary of the study stated that sleep loss could affect the resiliency of the stress response and may accelerate the development of metabolic and cognitive consequences of glucocorticoid excess.

So in summary, sleep deprivation can result in lowered growth hormone, reduced fat loss, increased loss of fat free mass, lowered calorie expenditure, elevated appetite, elevated cortisol and elevated blood glucose and insulin. Good luck improving your body composition with all of this going on.

Our next blog post will be on cheat meals and diet breaks which you can view here

References

Physiology of growth hormone secretion during sleep
https://www.ncbi.nlm.nih.gov/m/pubmed/8627466

Chronic lack of sleep is associated with increased sports injuries in adolescent athletes.
https://www.ncbi.nlm.nih.gov/m/pubmed/25028798

Insufficient sleep undermines dietary efforts to reduce adiposity
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951287/#!po=1.19048

Sleep disorders and the development of insulin resistance and obesity.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3767932/#!po=0.588235

Sleep loss results in an elevation of cortisol levels the next evening
https://www.ncbi.nlm.nih.gov/m/pubmed/9415946