Background: Physical Activity (PA) is currently considered as an essential element for a balanced lifestyle. Regular practice of PA and sports has a positive effect on several aspects of physical, psychological and biological health. It also improves adaptation to exercise. Having a better physical adaptation to exercise guarantees a good cardiorespiratory endurance which ensures better respiratory exchanges and better fitness condition. However, this adaptation to exercise may depend on certain associated factors. In Benin, a sub-Saharan African country, little is known about factors associated with physical adaptation to exercise, especially among young adults.

Purpose: To determine factors associated with physical adaptation to exercise in Beninese young adults.

Methods: Two hundred and eighteen young adults (157 males and 61 females) with mean age 22.21±3.22 years old were recruited in Benin. Age range was 18 to 30 years. The valid multistage step-test procedure of Nielens and Plaghki (1991) was used to determine the physical adaptation index to exercise (PW65%/kg) and the exertion perception index to exercise (RPE65%). Resting heart rate (HR0) and exercise volume were noted for each subject. To identify the factors associated with physical adaptation to exercise, we also collected socio-demographic data (sex, age, body mass index "BMI", ethnic group, religion, professional and marital status, dependent children, educational level, tobacco and alcohol consumption). Quality of life (QoL) and PA level were evaluated using the Short Form Health Survey (SF36) and Global Physical Activity Questionnaire (GPAQ) respectively. Data were summarized using descriptive statistic of frequency, percentages, mean and standard deviations. Multivariate linear regression was performed with socio-demographic data, HR0, RPE65%, exercise volume, SF36 total scores, GPAQ scores (independent variables) and PW65%/kg (dependent variable) to determine factors associated with physical adaptation to exercise.

Results: Mean±SD of BMI was 21.84±3.33 kg/m². Mean±SD of HR0 was 71.56±10.26 bpm. Mean±SD of PW65%/kg was 6.06±1.33. Mean±SD of RPE65% was 5.37±1.63. Mean±SD of SF36 total score was 74.80±12.38 and mean±SD of exercise volume was 5.88±1.05 stages. The PA level was low in 18.81% of the subjects, moderate in 23.39% and high in 57.80%. Regression model (R=0.79/R-squared=0.62) showed that only the factors such as exercise volume (β=0.53;p<0.001), RPE65% (β=0.35;p<0.001), sex (β=0.15; p<0.01) and PA level (β=0.10;p<0.01) were associated with PW65%/kg. The other model variables (p>0.05) were not associated with PW65%/kg. 62% of variances of PW65%/kg scores are explained by all of the independent variables studied.

Conclusion: Exercise volume, exertion perception during exercise, sex and physical activity level are linked to physical adaptation to exercise in young adults in Benin.

Implications: This study will allow physical activity professionals to take into account these factors identified as associated with adaptation in exercise programs to improve the subjects fitness condition.

Ethics approval: The study received approval from Health Sciences Faculty, University of Abomey-Calavi in Benin. Subjects signified their agreement to participate by signing a consent form.

Keywords: Young adults, Physical adaptation to exercise.