I am sad to have to report that the odd afternoon nap appears to significantly increase the risk of blood sugar elevation and diabetes.
For a while now, we have known that getting less than the optimal 7-8 hours of sleep at night can have a negative effect on insulin resistance and blood sugar levels, but now it appears that napping during daytime hours is also bad for our health.
A study recently published in Diabetes Care has found from a prospective study of nearly 175,000 people that those who napped for less than 1 hour a day increased their long term risk of developing elevated blood sugar levels by 23%. Those who napped for more than 1 hour a day increased their long term risk of developing elevated blood sugar levels by 55%! Even more recent research by Dr Shahrad Taheri of Birmingham University has found from studying 16,000 people that as little as one afternoon nap a week increases the risk of developing elevated blood sugar by 23%.
Xu Q, Song Y, Hollenbeck A, et al., Day napping and short night sleeping are associated with higher risk of diabetes in older adults, Diabetes Care, October 2009.
Taheri S, et al., Study details as presented at the Diabetes United Kingdom Annual Professional Conference in Glasgow 11 March 2009