Bright light influence on vasodilation induced by dynamic handgrip exercise

• Grant number: 20/11588-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): March 01, 2021
• Effective date (End): September 30, 2021
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Leandro Campos de Brito
• Grantee: Julia Maria Rosa da Silva
• Host Institution: Escola de Educação Física e Esporte (EEFE). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The vasodilation associated with adequate increase of blood flow (BF) during exercise is essential for performance, and is associated with oxygen uptake. Previous studies using models of dynamic handgrip exercise have demonstrated an increase of BF. The regulatory mechanisms of cardiovascular system and the BF per se present circadian patterns, such as most of physiological functions for human beings (i.e. nearly 24 hours cycles of a variable). This variation is coordinated by the biological clock, localized in the supraquiasmatic nucleus, which is synchronized by the light/dark cycle. Indeed, sympathetic nervous activity and blood pressure increase after exposition to bright light, it suggests an increase of vascular resistance underlying a decrease of BF at rest, while dim lights cause opposite effects, however it is not clear bright light effects during exercise on BF. The objective of this study is to assess if vasodilation during dynamic handgrip exercise is influenced by the intensity of light. For this, 10 healthy individuals (5 women, age 20-39 years), after exams for screening evaluation, will undergo for three experimental conditions under different bright light exposition in a random order, as following: elevated bright light (CE ~5000 lux), controlled bright light (CC ~200 lux) and dim light (PN d8 lux). At each of them, the subject will perform the dynamic handgrip exercise at 40% of maximal voluntary contraction performing cycles of contraction and relaxing of 2 s (i.e. 2:2 s) for 6 min. BF and vascular conductance of brachial artery (vascular ultrasound), blood pressure (photopletysmography) and heart rate will be continuously measured during 1 min at rest pre-exercise and during 6 min of exercise for each experimental condition. Two-way ANOVA for repeated measures will be employed, with the main factors bright light (CE, CC and PN) and the moment (pre- and exercise), P<0,05.

Scientific publications

(4)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

OLIVEIRA, GUSTAVO F.; MARIN, THAIS C.; APOLINARIO, NICOLAS; ROSA-SILVA, JULIA; AZEVEDO, LUAN; CECILIATO, JULIO; SILVA-BATISTA, CARLA; BRITO, LEANDRO C.. Association of morningness-eveningness preference with physical activity during the COVID-19 pandemic social distancing: a cross-sectional survey in Brazil Circadian rhythm, physical activity and isolation. CHRONOBIOLOGY INTERNATIONAL, MAY 2021. (18/05226-0, 20/11588-2)

ROSA-SILVA, JULIA; THOSAR, SAURABH; AZEVEDO, LUAN; FORJAZ, CLAUDIA; BRITO, LEANDRO. BRIGHT LIGHT EXPOSITION POTENTIATES THE VASODILATION PROMOTED BY DYNAMIC HANDGRIP EXERCISE. Sleep, v. 45, p. 1-pg., 2022-06-01. (20/11588-2)

OLIVEIRA, GUSTAVO F.; MARIN, THAIS C.; APOLINARIO, NICOLAS; ROSA-SILVA, JULIA; AZEVEDO, LUAN; CECILIATO, JULIO; SILVA-BATISTA, CARLA; BRITO, LEANDRO C.. Association of morningness-eveningness preference with physical activity during the COVID-19 pandemic social distancing: a cross-sectional survey in Brazil Circadian rhythm, physical activity and isolation. CHRONOBIOLOGY INTERNATIONAL, v. 38, n. 10, p. 1432-1440, OCT 3 2021. (18/05226-0, 20/11588-2)

BRITO, LEANDRO C.; MARIN, THAIS C.; AZEVEDO, LUAN; ROSA-SILVA, JULIA M.; SHEA, STEVEN A.; THOSAR, SAURABH S.. Chronobiology of Exercise: Evaluating the Best Time to Exercise for Greater Cardiovascular and Metabolic Benefits. COMPREHENSIVE PHYSIOLOGY, v. 12, n. 3, p. 19-pg., 2022-07-01. (20/11588-2, 18/05226-0)