Sustained Sleep Restriction Reduces Resistance Exercise Quality and Quantity in Females

Abstract

IntroductionFemale athletes sleep less and report more sleep problems than their male counterparts. Inadequate sleep reduces maximal strength in male athletes; however, little is known about the impact of sleep restriction (SR) on the quantity and quality of resistance exercise performed by female athletes. This study investigated the effect of nine nights of moderate SR on repeated resistance exercise performance, hormonal responses, and perceived fatigue in females.MethodsTen healthy, resistance-trained, eumenorrheic females age 18–35 yr underwent nine nights of SR (5-h time in bed) and normal sleep (NS; ≥7-h time in bed) in a randomized, crossover fashion with a minimum 6-wk washout. Participants completed four resistance exercise sessions per trial, with blood samples collected before and after exercise. Exercise performance was assessed using volume load, reactive strength index, and mean concentric velocity with rating of perceived exertion recorded after exercise. Participants completed awakening saliva sampling and the Multi-component Training Distress Scale daily.ResultsVolume load decreased trivially (<1%, P < 0.05) with SR. Mean concentric velocity per set was slower during SR for the lower-body (up to 15%, P < 0.05), but not the upper-body, compound lifts. Intraset velocity loss was up to 7% greater during SR for back squats (P < 0.05). SR increased salivary cortisol area under the curve (by 42%), total training distress (by 84%), and session perceived exertion (by 11%).ConclusionsSustained SR reduces markers of resistance exercise quality (bar velocity) more than quantity (volume load) and increases perceived effort at the same relative intensity in resistance-trained females. Markers of exercise quality and internal load may be more sensitive than volume load, to advise coaches to the decline in lifting performance for female athletes experiencing SR.

The interactive effect of sustained sleep restriction and resistance exercise on skeletal muscle transcriptomics in young females

“…At the time of study design, no similar human studies examining sleep restriction and molecular markers of muscle adaptation (to resistance exercise) existed on which to base sample size calculations. Therefore, the power calculation was determined for the primary outcome measure of the broader study only (resistance exercise volume load), and all other measures were included as secondary analysis (21).…”

“…This study is a sub-component of a broader study investigating the effect of sustained sleep restriction on muscle strength performance, and the participant inclusion and exclusion criteria have been described elsewhere (21). All participants regularly slept >7 h per night and had a ‘moderately morning’ or ‘neither’ chronotype classification, as determined using a combination of actigraphy and self-report measures, and the morningness-eveningness questionnaire (22), respectively.…”

“…All participants were eumenorrheic (i.e., menstruation occurs consistently on a 21- to 35-day cycle). While recent research suggests a minimal effect of menstrual cycle phase on muscle strength (24), we still aimed to minimize any potential confounding impact (25) on any other muscle outcome, and a detailed account of the strategy used to minimize the effects of menstrual cycle fluctuations, participant ovarian hormone data and menstrual phase identification can be found elsewhere (21).…”

“…This study was approved by the Deakin University Human Research Ethics Committee (DUHREC 2017-305) and conducted in accordance with The Declaration of Helsinki (1964) and its later amendments. The pre-condition, sleep restriction (SR) condition and normal sleep (NS) condition protocols are described in detail elsewhere (21). Briefly, participants attended the laboratory on two occasions prior to the experimental conditions to 1) provide written informed consent, undertake a baseline blood sample and 3-repetition maximum strength measurements and, 2) complete a resistance exercise session familiarisation.…”

“…Resistance exercise is known to induce a large, but transient transcriptional response, which is thought to underpin the associated increases in strength and muscle mass (20). We have previously shown that sleep restriction impairs resistance exercise performance (21), but how sleep restriction may impact the muscle molecular response to resistance exercise over time is unknown.…”