SLEEP – LOSING BODY FAT


7 RESEARCH ARTICLES + 3 GRAPHICS – CLICK ON GRAPHICS TO ENLARGE



 January – 2018
Lack of sleep may impact:
a) immune function
b) cognitive performance
c) hunger
d) endocrine function
– Too little sleep not only decreases fat loss during a diet, but also increases muscle loss (lean body mass)
– One study observed 55% less fat loss and 60% more lean body mass loss in dieting subjects that had a 5.5 h time in bed compared to 8.5 h time in bed (TIB)
– One of the possible mechanisms is that the 5.5 TIB group had higher concentrations of acylated (activated) ghrelin, which is known as the ‘hunger hormone’
– However, acylated ghrelin has also been shown to increase lipid accumulation in cell and animal studies
– In addition, acylated ghrelin has been shown to increase glucose production in the liver
– This suggests that instead of burning fat as fuel, muscle tissue was broken down to produce glucose which was burned instead of fat
– This was supported by the respiratory quotient
– The subjects were kept at the university for 14 days, and all their food was provided
– This is important, as a lack of sleep can increase hunger and would therefore likely result in different eating patterns between the groups
– Also, note that time in bed is not the same as sleep. The actual amount of sleep will of course be lower than the time spent in bed
Study: https://www.ncbi.nlm.nih.gov/pubmed/20921542
Other references:
1) https://www.ncbi.nlm.nih.gov/pubmed/8238617
2) https://www.ncbi.nlm.nih.gov/pubmed/12603781
3) https://www.ncbi.nlm.nih.gov/pubmed/24965304
4) https://www.ncbi.nlm.nih.gov/pubmed/10543671
5) https://www.ncbi.nlm.nih.gov/pubmed/11057670
6) https://www.ncbi.nlm.nih.gov/pubmed/18433874

 

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