Changes in submaximal and maximal measures of cardio-respiratory fitness resulting from 6-days of mountain walking.

Trekking is a popular activity associated with cardiovascular benefits. The aim of the present study was to investigate changes in the submaximal heart rate, oxygen uptake, oxygen pulse, and blood lactate concentration associated with a 6-day mountain walk. Over a 12-year period, 134 male (age 21.0 ± 1.4 years) and 124 female undergraduates (age 20.8 ± 1.6 years) participated. Three days before the trek submaximal and maximal laboratory measures were made on participants walking on a motorized treadmill using a breath-by-breath system to measure oxygen uptake (VO2) during exercise. Oxygen uptake and heart rate were recorded during steady-state exercise at treadmill gradients 0, 4, 8, 12, and 16%. Measurements were made, at the same time of day, two days after the trek. There were significant improvements in both the walking economy and the relative exercise intensity (%VO2max) at submaximal treadmill gradients 0-16%. Post-trek, heart rate was lower while oxygen pulse was higher, at each treadmill gradient. There was a significant increase in the maximal oxygen uptake for men (+2.7%) and women (+2.9%). The results of the present study suggest that improvements in cardiorespiratory fitness are associated with a 6-day mountain walk with no sex difference in the exercise response.      .