Can two weeks of sprint interval training improve health related fitness In overweight/obese sedentary males?

Physical activity is known to be beneficial to health and many studies have investigated the efficacy of moderate and high intensity exercise to improve health related parameters (e.g. Houmard et al., J Appl Physiol 96: 101-6, 2004). However, little is known as to whether shorter duration, higher intensity exercise (e.g. "all-out" sprinting) also provides health benefits.PURPOSE: To investigate whether very high intensity sprint interval training (SIT) improves health related fitness.METHODS: Nine sedentary males (Age: 31.3 ± 8.8 yrs, body mass index (BMI): 31.1 ± 3.9 kg/m2, percentage fat: 28.7 ± 5.1%) were recruited. Fasted, resting metabolic assessment, plus anthropometric and fitness measurements were made before and after subjects completed a two week SIT intervention. The SIT involved six sessions of 4-6 repeats of 30 sec Wingate Anaerobic sprints on an electromagnetically controlled ergometer, with 4.5 min of recovery between repetitions.RESULTS: Two weeks of SIT improved fitness as both Wingate Anaerobic mean power (567 ± 69 vs. 587 ± 61 W; P = 0.037) and VO2max (2.95 ± 0.50 vs. 3.18 ± 0.44 l/min; P = 0.029) were significantly improved from pre to post intervention. Furthermore, several health related parameters also changed: mean blood pressure (94.8 ± 9.63 vs. 89.7 ± 9.46 mmHg; P < 0.001), fasted resting respiratory exchange ratio (0.77 ± 0.04 vs. 0.73 ± 0.04; P = 0.036) and waist to hip ratio (0.92 ± 0.07 vs. 0.90 ± 0.07; P = 0.044) were all significantly reduced. BMI, weight and the sum of 4 sites skinfold thickness did not change significantly (31.1 ± 3.88 vs. 30.7 ± 4.02 kg/m2; P = 0.054, 92.9 ± 13.12 vs. 91.9 ± 13.63; P = 0.067 and 110.4 ± 21.9 vs. 105.3 ± 26.8; P = 0.073 respectively). In addition, the area under the curve (AUC) for blood glucose during an oral glucose tolerance test (OGTT) was unchanged (845.6 ± 348.8 vs. 802.7 ± 338.0 mmol/l.min; P = 0.59). However, fasted triglyceride concentration was significantly reduced (1.35 ± 0.56 vs. 1.17 ± 0.31 mmol/l; P = 0.028) and non-esterified fatty acid concentration AUC during an OGTT significantly decreased (39.68 ± 26.05 vs. 16.42 ± 9.63 mmol/l.min; P = 0.018).CONCLUSIONS: Two weeks of a SIT intervention substantially improves many health related parameters in overweight/obese sedentary males.