Affiliation:
1. Institute of Biological Sciences, Department of Physiology,
Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil
2. Department of Sport Sciences/Institute of Health Sciences,
Federal University of Triangulo Mineiro, UBERABA, Brazil
Abstract
AbstractWe analyzed the effects of wearing blue lenses on melatonin level, physical and
cognitive performance. Fifteen youth volleyball players
(15.0±1.5 yrs) attended the laboratory on 3 occasions (48-h
interval): on the 1st visit they were familiarized with the
procedures of the study, and on 2nd and 3rd visits they
were submitted to the testing protocol wearing transparent (control) or blue
lens glasses in a counterbalanced crossover design. The protocol consisted of
10 min in “total darkness,” 30 min of light
stimulation (wearing blue or transparent lenses), followed by an attentional
test, and an agility T-test (without wearing the glasses). Samples of saliva (to
determine melatonin concentration) were obtained pre- and post-exposure
(30 min) to artificial light, wearing the lenses. Sleepiness, alertness,
attention, mood, and perceived recovery status and performance variables
(reaction time and T-test) were assessed after lens exposure. Melatonin levels
did not differ within and between groups (blue lenses, pre: 0.79±0.73
and post: 1.19±1.374 pg/dl, p=0.252, effect size
(ES)=0.38; control, pre: 0.97±1.00 and post:
0.67±0.71 pg/dl, p=0.305,
ES=–0.35). Nonetheless, melatonin differences were significantly
correlated with physical sedation for glasses with blue lenses
(r=−0.526; p=0.04). No other variables differed
(p>0.05) between protocols, including T-test performance
(p=0.07; ES=0.41). Blue lenses do not influence melatonin
levels, cognitive/physical performance, and mood status in amateur youth
volleyball players.