Benefits of training at moderate altitude versus sea level training in amateur runners.

After more than 25 years of research of altitude training (AT) there is no consensus regarding either the training programme at altitude or the effects of AT on performance at sea level. Based on a review of the research work on AT, we investigated combined base training and interval training at moderate altitude and compared immediate and delayed effects on sea level performance with those following similar sea level training (SLT). The altitude group (AG, 10 male amateur runners) trained at 2315 m (natural altitude) and the sea level group (SLG, 12 male amateur runners) at 187 m. Both groups performed 7 days of base training (running on a trail) lasting between 60 and 90 min a day and 5 days of interval training (speed and hill runs) for between 10 and 45 min a day. Incremental exercise tests were performed 1 week before (t1), 3 days after (t2) and 16 days after (t3) the 12-day main training period. Within AG, exercise performance improved from t1 to t2 by 8% (P < 0.05) and from t2 to t3 by 8% (P < 0.05). Maximum oxygen uptake (VO2max) increased from t2 to t3 by 10% (P < 0.05). Within SLG exercise performance increased from t2 to t3 by 8% (P < 0.05). At t3, relative and absolute VO2max in AG were significantly higher in comparison with SLG (P = 0.005 and P = 0.046 respectively). The improved performance 3 days after AT may be explained in part by an increased oxygen uptake at submaximal exercise intensities without a change in VO2max. Further enhancement in performance 2 weeks after AT, however, seems to have been due to the clearly enhanced VO2max. Progressive cardiovascular adjustments might have contributed primarily to the time-dependent improvements observed after AT, possibly by an enhanced stroke volume overcompensating the reduced heart rates during submaximal exercise. In conclusion, our findings would suggest that training at a moderate natural altitude improves performance at sea level more than SLT. Combining base and interval training with regulation of intensity by training at constant heart rates during acclimatization at altitude would seem to be a successful training regimen for amateur runners. Most beneficial effects became apparent during the subsequent SLT around 2 weeks after return from altitude. Therefore, we are convinced that AT should be reconsidered as a potent tool for enhancing aerobic capacity, at least in non-elite athletes.