Age and gender patterns of human cardiorespiratory fitness in the conditions of the urbanized Siberian North

Aim. The aim of this article is to reveal consistent patterns of human cardiorespiratory system reaction to walking at different speeds depending on sex and age in the conditions of the urbanized Siberian North. Materials and Methods. We studied three groups of healthy volunteers. The group of young people (GY, 22.1 ± 2.6 years, n = 25: 12 men and 13 women), the group of middle-aged people (GM, 42.7 ± 9.3 years, n = 25: 12; 13) and the elderly group (GE, 66.2 ± 5.1 years, n = 24: 11, 13) performed walking on the treadmill at a speed of 2-7 km/h for 5 minutes at each speed. We used FitMet PRO analyzer (COSMED, Italy) to measure breathing frequency (FB, times/min), lungs ventilation (VE, l/min), oxygen consumption (PO2, ml/min), relative oxygen consumption (RPO2, ml/min/kg), heart rate (HR, bpm), and oxygen concentration in the exhaled air (KO2, %). Before the beginning of the study, we measured leg length (m), body length (m), and body weight (kg). Results. As walking speed increased from 2 to 7 km/h, relative oxygen consumption increased regularly in the young group by 14.6 ml/kg/min (2.46 times), in the middle-aged group by 17 ml/kg/min (2.72 times), and in the elderly group by 13.9 ml/kg/min (2.53 times). We registered the decrease in the slope of the dependence curves of relative oxygen consumption on heart rate in young and older women in comparison with young people and the people of middle and old age. Regression equations of the dependence of relative oxygen consumption on pulmonary ventilation (VO2 = -12.9 + 40.3Ve (r =.98, p =.0000) in young men and VO2 = 116.3 + 34.7Ve in girls (r =.97; p =.0000)) allow to determine oxygen consumption in the group of students in the classroom using a spirometer. Conclusion. The data obtained show that the reaction of the cardiorespiratory system of the persons of different ages in response to walking with a stepwise increasing rate is adequate. Decrease in the slope of the dependence curves of relative oxygen consumption on heart rate in young and elderly women in comparison with young people, middle-aged and elderly people indicates a possible decrease in the cardiorespiratory endurance of women from this sample.