Garry S. Palmer

Water ingestion does not improve 1-h cycling performance in moderate ambient temperatures.

Eight endurance-trained cyclists rode as far as possible in 1 h on a stationary cycle simulator in a moderate environment (20°C, 60% relative humidity, 3 m·s−1 wind speed) while randomly receiving either no fluid (NF) or attempting to replace their approximate 1.71 sweat loss measured in a previous 1-h familiarisation performance ride at approximately 85% of peak oxygen uptake with artificially sweetened, coloured water (F). During F, the cyclists drank mean 1.49 (SEM 0.14)1 of which mean 0.27 (SEM 0.08)1 remained in the stomach at the end of exercise and mean 0.20 (SEM 0.05) 1 was urinated after the trial. Thus, only mean 1.02 (SEM 0.12)1 of the ingested fluid was available to replace sweat losses during the 1-h performance ride. That fluid decreased the mean average heart rate from 166 (SEM 3) to 157 (SEM 5) beats·min−1 (P < 0.0001) and reduced the final mean serum [Na−] and osmolalities from 143 (SEM 0.6) to 139 (SEM 0.6) matom·1−1(P < 0.005) and from 294 (SEM 1.7) to 290 (SEM 1.9) mosmol·1−1 (P = 0.05), respectively. Fluid ingestion did not significantly attenuate rises in plasma anti-diuretic hormone and angiotensin concentrations, or decrease the approximate-15% falls in estimated plasma volume in the F and NF trials. Nor did fluid ingestion significantly affect the approximate 1.71 · h−1 sweat rates, the rises in rectal temperature (from 36.6° to 38.3°C) or the ratings of perceived exertion in the two trials. Ingestion of approximately 1.51 of fluid produced an uncomfortable feeling of stomach fullness and reduced the mean distance covered in 1 h from 43.1 (SEM 0.7) to 42.3 (SEM 0.6) km (P < 0.05). Thus, trying to replace more than 1.01·h−1 sweat losses during high-intensity, short duration exercise in a moderate environment would not appear to induce beneficial physiological effects, and may impair exercise performance.

Heart rate responses during a 4-d cycle stage race.

The purpose of this study was to monitor the heart rates (HR) of seven, well-trained (maximal oxygen uptake [VO2max] 5.0 +/- 0.5 l.min-1), competitive cyclists during a 4-d cycle stage race. On consecutive days, subjects competed in a 16.0-km individual time trial (TT), a 110.0-km mass-start road race (RR1), a 5.5-km individual hill climb (HC), and a 105.0-km mass-start road race (RR2). Within 10 d of the final race, cyclists underwent a test to determine VO2max, peak power output, and maximal HR. Comparison of the HR responses to each race revealed that the individual events were performed at a relatively high and constant work rate (91.1 +/- 2.5% and 93.2 +/- 4.7% of the maximal HR as measured in the field (HRmax) for the TT and HC, respectively). In contrast, despite similar racing speeds (42.2 +/- 1.0, 39.9 +/- 0.2, and 40.6 +/- 0.5 km.h-1 for the TT, RR1, and RR2, respectively), the HR responses to the longer mass-start races were reduced to 81.9 +/- 9.6% and 78.6 +/- 8.9% of HRmax and were random in frequency and amplitude. Such stochastic changes in HR were seemingly unrelated to course terrain but may be due to the group dynamics of the cyclists. The results of this study reveal the stochastic nature of bunch cycle racing and show that the HR responses of competitive cyclists are more a function of tactical bunch riding than of terrain.

Effects of chronic bicarbonate ingestion on the performance of high-intensity work

Abstract We have evaluated whether sodium bicarbonate, taken chronically (0.5 g · kg−1 body mass) for a period of 5 days would improve the performance of eight subjects during 60 s of high-intensity exercise on an electrically braked cycle ergometer. The first test was performed prior to chronic supplementation (pre-ingestion) while the post-ingestion test took place 6 days later. A control test took place approximately 1 month after the cessation of all testing. Acid-base and metabolite data (n = 7) were measured from arterialised blood both pre- and post-exercise, as well as daily throughout the exercise period. The work completed by the subjects in the control and pre-ingestion test [21.1 (0.9) and 21.1 (0.9) MJ, respectively] was less than (P < 0.05) that completed in the post-ingestion test [24.1 (0.9) MJ; F(2,21) = 3.4, P < 0.05, power = 0.57]. Peak power was higher after the 5-day supplementation period (P < 0.05). Ingestion of the sodium bicarbonate for a period of 5 days resulted in an increase in pH (F(5,36) = 12.5, P < 0.0001, power = 1.0) over the 5-day period. The blood bicarbonate levels also rose during the trial (P < 0.05) from a resting level of 22.8 (0.4) to 28.4 (1.1) mmol · l−1 after 24 h of ingestion. In conclusion, the addition of sodium bicarbonate to a normal diet proved to be of ergogenic benefit in the performance of short-term, high-intensity work.

Effects of steady-state versus stochastic exercise on subsequent cycling performance

The aims of this investigation were to evaluate the physiological responses to laboratory based stochastic exercise and to assess the effects of stochastic versus steady-state exercise on subsequent cycling time trial (TT) performance. Six competitive cyclists (peak power output (PPO) 432 +/- 39 W (values are mean +/- SD) undertook in a random order two 150-min paced rides that were either constant load (58% of PPO) or stochastic in nature (58 +/- 12.2% of PPO). These rides were immediately followed by a 20-km TT performance on an air-braked ergometer. Mean heart rate (HR) responses throughout the 150-min paced rides and during the subsequent TT were not significantly different between trials. Yet, despite the similarities in HR, the mean time for the TT was significantly faster (26:32 +/- 1:30 vs 28:08 +/- 1:47 min, P < 0.05) and the mean power output was significantly greater (340.3 +/- 44.2 vs 302.5 +/- 42.3 W; 77.8 +/- 10.2 vs 70.0 +/- 9.8% of PPO, P < 0.05) following the steady-state ride. These results demonstrate that following 150 min of steady-state riding, subsequent 20 km TT performance was significantly improved when compared with 150 min of stochastic exercise.

The effects of differing environmental conditions on the performance and recovery from high-intensity, intermittent cycle ergometry

The aim of this experiment was to determine the effects of 3 different environmental conditions on the performance and recovery from short-term, high-intensity, anaerobic-type exercise. Eight males (age = 25.5 ± 1.8 years; height = 179.0 ± 3.7 cm; weight = 72.3 ± 4.0 kg; Vo2max = 51.5 ± 2.4 ml·kg−1·min−1, peak aerobic power 366 ± 13 W) volunteered for this study. After undertaking Vo2max testing, all participated randomly in 3 consecutive 30-second Wingate tests (WAnT) in 3 different environmental conditions: normal (22° C/30% RH), humid (30° C/85% RH), and hot (40° C/40% RH). Subjects were then monitored for the 60-minute postexercise period. Blood samples were taken pre-, immediately postexercise, and at 1, 5, 10, 15, 30, 45, and 60 minutes into the recovery period and analyzed for lactate, pH, and hematocrit. Weight was measured preexercise and at 15, 30, 45, and 60 minutes postexercise. The results of the tests indicate that there were no changes in the subjects body weight between tests or in the recovery period. The mean peak power values achieved were 897.9 ± 18.8, 832.5 ± 16.4, and 798.8 ± 21.0 W for WAnT test 1, 2, and 3, respectively, which were not significantly different in the 3 conditions, but were significantly different from each other p <0.02 and p <0.0004 for comparisons of 1v2 and 2v3, respectively. Other data showed no significant differences between the conditions during the exercise or the 60-minute recovery period. The results suggest that in both the hot and humid conditions seen in our experiment, there was no adverse affect on the performance of the WAnT test.