Brief Intense Stair Climbing Improves Cardiorespiratory Fitness

Purpose: Sprint interval training (SIT) is a time-efficient strategy to improve cardiorespiratory fitness (CRF); however, most protocols have been studied in laboratory settings and require specialized equipment. We investigated the efficacy of brief intense stair climbing as a practical model of SIT to improve CRF. Methods: Two separate studies, each consisting of an acute and chronic phase, were conducted in a total of 31 sedentary women (age = 24 +/- 10 yr, body mass index = 23 +/- 4 kg.m(-2)). Results: The acute phase of study 1 established that the mean HR, blood [lactate], and RPE were similar when participants (n = 8) performed an SIT protocol that involved 3 x 20-s all-out efforts of either continuously ascending stairs or cycling. The chronic phase demonstrated that CRF, as determined by peak oxygen uptake ((V) over dotO(2peak)), increased by 12% or similar to 1 MET (8.27 +/- 1.05 to 9.25 +/- 1.01 METs, P = 0.002) when participants (n = 12) performed the 3 x 20-s stair climbing protocol 3 d.wk(-1) for 6 wk. The acute phase of study 2 established that HR and RPE were similar when participants (n = 11) performed three different stair climbing protocols: the 3 x 20-s continuous ascent model used in study 1 and two 3 x 60-s models of ascending and descending either one or two flights of stairs (P > 0.05). The chronic phase demonstrated that (V) over dotO(2peak) increased by 7% (8.91 +/- 1.30 to 9.51 +/- 1.52 METs, P = 0.01) when the same group of participants performed the one-flight 3 x 60-s protocol 3 d.wk(-1) for 6 wk. The Cederholm index determined from an oral glucose tolerance test was 57 +/- 17 and 64 +/- 21 mg.L-2.mmol(-1).mU(-1).min(-1) before and after training, respectively (P = 0.056). Conclusion: Brief, intense stair climbing is a practical, time-efficient strategy to improve CRF in previously untrained women.