Mar 27, 2019

Physio Student Kelly Ness Publishes Paper in American Journal of Physiology

Ness, who previously served as Graduate Adviser to the Huck Institutes, simulated a seven-day working working week to study recovery of insulin sensitivity.

Kelly Ness, a graduate student in the Huck Institutes' Integrative and Biomedical Physiology program, is the first author of a new paper appearing in the American Journal of Physiology — Regulatory, Integrative and Comparative Physiology.

Ness's paper, titled "Two Nights of Recovery Sleep Restores the Dynamic Lipemic Response, but Not the Reduction of Insulin Sensitivity, Induced by Five Nights of Sleep Restriction" assessed the effects of sleep restriction and subsequent recovery sleep on insulin sensitivity and fat metabolism.

Ness's team simulated a typical working week for many adults—five days of less than ideal sleeping hours followed by two nights of extended rest—and they found that the damage done by the restricted sleep was not undone by sleeping in on the "weekend."

"We found that in our population of young, healthy men (who had a relatively long habitual sleep time of 8.3 hr/night), two nights of 10 hrs/night sleep opportunity was not enough to restore insulin sensitivity to baseline values," said Ness. "We also found that sleep restriction suppresses the rebound of non-esterified fatty acids (NEFA), but that the rebound was restored to baseline values following two nights of recovery sleep.

"We were surprised that two nights of recovery sleep did not restore insulin sensitivity. We designed this study to mimic a ‘work week’ with five nights of sleep restriction (aka a work week) followed by two nights of recovery (aka a weekend). This finding implies that a weekend of catch up sleep may not be enough for some people to regain healthy metabolic function. We were also surprised that the rebound in NEFA was affected by sleep restriction. It’s too early to say, but this could mean that skeletal muscle undergoes a shift in fuel selection in response to sleep restriction, preferring fat to glucose and contributing to the observed decreases in insulin sensitivity."