Effects of Heat Acclimatization, Heat Acclimation, and Intermittent Exercise Heat Training on Time-Trial Performance

2021 ◽  
pp. 194173812110506
Author(s):  
Yasuki Sekiguchi ◽  
Courteney L. Benjamin ◽  
Ciara N. Manning ◽  
Jeb F. Struder ◽  
Lawrence E. Armstrong ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Statistical Significance ◽  
Time Trial ◽  
Heat Acclimation ◽  
Peak Oxygen Consumption ◽  
Heat Acclimatization ◽  
Level Of Evidence ◽  
Time Trial Performance ◽  
Level 3 ◽  
Trial Performance

Background: The purpose of this study was to investigate effects of heat acclimatization (HAz) followed by heat acclimation (HA), and intermittent heat training (IHT) on time-trial performance. Hypothesis: Time-trial performance will improve after HA and will further improve with twice a week of IHT. Study Design: Interventional study. Level of Evidence: Level 3. Methods: A total of 26 male athletes (mean ± SD; age, 35 ± 12 years; body mass, 72.8 ± 8.9 kg; peak oxygen consumption [VO2peak], 57.3 ± 6.7 mL·kg−1·min−1) completed five 4-km time trials (baseline, post-HAz, post-HA, post-IHT4, post-IHT8) in the heat (ambient temperature, 35.4°C ± 0.3°C; relative humidity, 46.7% ± 1.2%) on a motorized treadmill. After baseline time trial, participants performed HAz (109 ± 10 days) followed by post-HAz time trial. Then, participants completed 5 days of HA, which involved exercising to induce hyperthermia (38.50°C-39.75°C) for 60 minutes. Participants were then divided into 3 groups and completed IHT either twice per week (IHTMAX), once per week (IHTMIN), or not at all (IHTCON) over an 8-week period. The exercise used for the IHT matched the HA. Four-kilometer time trials were performed after 4 weeks (post-IHT4) and 8 weeks of IHT (post-IHT8). Results: Time trial was faster in post-HA (17.98 ± 2.51 minutes) compared with baseline (18.61 ± 3.06 minutes; P = 0.037) and post-HAz (18.66 ± 3.12 minutes; P = 0.023). Percentage change in time trial was faster in IHTMAX (−3.9% ± 5.2%) compared with IHTCON (11.5% ± 16.9%) ( P = 0.020) and approached statistical significance with large effect (effect size = 0.96) compared with IHTMIN (1.6% ± 6.2%; P = 0.059) at post-IHT8. Additionally, IHTMAX (−2.2% ± 4.2%) was faster than IHTCON (3.6% ± 6.9%) ( P = 0.05) at post-IHT4. Conclusion: These results indicate that HA after HAz induces additional improvement in time-trial performance. IHT twice per week shows improvement after 8 weeks, while once per week maintains performance for 8 weeks. No IHT results in a loss of adaptations after 4 weeks and even greater losses after 8 weeks. Clinical Relevance: HA after HAz improves time-trial performance, twice a week of IHT improves performance further, and once a week of IHT maintains performance for at least 8 weeks.

Effect of 8 days of exercise-heat acclimation on aerobic exercise performance of men in hypobaric hypoxia

2020 ◽  
Vol 319 (1) ◽  
pp. R114-R122
Author(s):  
Roy M. Salgado ◽  
Kirsten E. Coffman ◽  
Karleigh E. Bradbury ◽  
Katherine M. Mitchell ◽  
Beau R. Yurkevicius ◽  
...  
Keyword(s):  
Steady State ◽  
Exercise Performance ◽  
Hypobaric Hypoxia ◽  
Acute Mountain Sickness ◽  
Time Trial ◽  
Heat Acclimation ◽  
Peak Oxygen Consumption ◽  
Time Trial Performance ◽  
Expansion Time ◽  
Trial Performance

Exercise-heat acclimation (EHA) induces adaptations that improve tolerance to heat exposure. Whether adaptations from EHA can also alter responses to hypobaric hypoxia (HH) conditions remains unclear. This study assessed whether EHA can alter time-trial performance and/or incidence of acute mountain sickness (AMS) during HH exposure. Thirteen sea-level (SL) resident men [SL peak oxygen consumption (V̇o2peak) 3.19 ± 0.43 L/min] completed steady-state exercise, followed by a 15-min cycle time trial and assessment of AMS before (HH1; 3,500 m) and after (HH2) an 8-day EHA protocol [120 min; 5 km/h; 2% incline; 40°C and 40% relative humidity (RH)]. EHA induced lower heart rate (HR) and core temperature and plasma volume expansion. Time-trial performance was not different between HH1 and HH2 after 2 h (106.3 ± 23.8 vs. 101.4 ± 23.0 kJ, P = 0.71) or 24 h (107.3 ± 23.4 vs. 106.3 ± 20.8 kJ, P > 0.9). From HH1 to HH2, HR and oxygen saturation, at the end of steady-state exercise and time-trial tests at 2 h and 24 h, were not different ( P > 0.05). Three of 13 volunteers developed AMS during HH1 but not during HH2, whereas a fourth volunteer only developed AMS during HH2. Heat shock protein 70 was not different from HH1 to HH2 at SL [1.9 ± 0.7 vs. 1.8 ± 0.6 normalized integrated intensities (NII), P = 0.97] or after 23 h (1.8 ± 0.4 vs. 1.7 ± 0.5 NII, P = 0.78) at HH. Our results indicate that this EHA protocol had little to no effect—neither beneficial nor detrimental—on exercise performance in HH. EHA may reduce AMS in those who initially developed AMS; however, studies at higher elevations, having higher incidence rates, are needed to confirm our findings.

scholarly journals Effects Of Heat Acclimatization, Heat Acclimation And Intermittent Heat Training On Time-trial Performance

2021 ◽  
Vol 53 (8S) ◽  
pp. 348-348
Author(s):  
Yasuki Sekiguchi ◽  
Courteney L. Benjamin ◽  
Ciara N. Manning ◽  
Jeb F. Struder ◽  
Lawrence E. Armstrong ◽  
...  
Keyword(s):  
Time Trial ◽  
Heat Acclimation ◽  
Heat Acclimatization ◽  
Time Trial Performance ◽  
Trial Performance

scholarly journals Short-Term Heat Acclimation and Precooling, Independently and Combined, Improve 5-km Time Trial Performance in the Heat

2018 ◽  
Vol 32 (5) ◽  
pp. 1366-1375 ◽  
Author(s):  
Carl A. James ◽  
Alan J. Richardson ◽  
Peter W. Watt ◽  
Ashley G.B. Willmott ◽  
Oliver R. Gibson ◽  
...  
Keyword(s):  
Time Trial ◽  
Heat Acclimation ◽  
Short Term ◽  
Time Trial Performance ◽  
Trial Performance

scholarly journals The Relationship Between the Distribution of Training Intensity and Performance of Kayak and Canoe Sprinters: A Retrospective Observational Analysis of One Season of Competition

2022 ◽  
Vol 3 ◽  
Author(s):  
Manuel Matzka ◽  
Robert Leppich ◽  
Hans-Christer Holmberg ◽  
Billy Sperlich ◽  
Christoph Zinner
Keyword(s):  
Time Trial ◽  
Individual Variability ◽  
Peak Oxygen Consumption ◽  
Entire Group ◽  
Training Intensity ◽  
Training Time ◽  
Time Trial Performance ◽  
The Individual ◽  
Time Required ◽  
Trial Performance

Purpose: To evaluate retrospectively the training intensity distribution (TID) among highly trained canoe sprinters during a single season and to relate TID to changes in performance.Methods: The heart rates during on-water training by 11 German sprint kayakers (7 women, 4 men) and one male canoeist were monitored during preparation periods (PP) 1 and 2, as well as during the period of competition (CP) (total monitoring period: 37 weeks). The zones of training intensity (Z) were defined as Z1 [<80% of peak oxygen consumption (VO2peak)], Z2 (81–87% VO2peak) and Z3 (>87% VO2peak), as determined by 4 × 1,500-m incremental testing on-water. Prior to and after each period, the time required to complete the last 1,500-m stage (all-out) of the incremental test (1,500-m time-trial), velocities associated with 2 and 4 mmol·L−1 blood lactate (v2[BLa], v4[BLa]) and VO2peak were determined.Results: During each period, the mean TID for the entire group was pyramidal (PP1: 84/12/4%, PP2: 80/12/8% and CP: 91/5/4% for Z1, Z2, Z3) and total training time on-water increased from 5.0 ± 0.9 h (PP1) to 6.1 ± 0.9 h (PP2) and 6.5 ± 1.0 h (CP). The individual ranges for Z1, Z2 and Z3 were 61–96, 2–26 and 0–19%. During PP2 VO2peak (25.5 ± 11.4%) markedly increased compared to PP1 and CP and during PP1 v2[bla] (3.6 ± 3.4%) showed greater improvement compared to PP2, but not to CP. All variables related to performance improved as the season progressed, but no other effects were observed. With respect to time-trial performance, the time spent in Z1 (r = 0.66, p = 0.01) and total time in all three zones (r = 0.66, p = 0.01) showed positive correlations, while the time spent in Z2 (r = −0.57, p = 0.04) was negatively correlated.Conclusions: This seasonal analysis of the effects of training revealed extensive inter-individual variability. Overall, TID was pyramidal during the entire period of observation, with a tendency toward improvement in VO2peak, v2[bla], v4[bla] and time-trial performance. During PP2, when the COVID-19 lockdown was in place, the proportion of time spent in Z3 doubled, while that spent in Z1 was lowered; the total time spent training on water increased; these changes may have accentuated the improvement in performance during this period. A further increase in total on-water training time during CP was made possible by reductions in the proportions of time spent in Z2 and Z3, so that more fractions of time was spent in Z1.

scholarly journals Heat acclimation improves exercise performance

2010 ◽  
Vol 109 (4) ◽  
pp. 1140-1147 ◽  
Author(s):  
Santiago Lorenzo ◽  
John R. Halliwill ◽  
Michael N. Sawka ◽  
Christopher T. Minson
Keyword(s):  
Exercise Performance ◽  
Lactate Threshold ◽  
Time Trial ◽  
Heat Acclimation ◽  
Control Group ◽  
Time Trial Performance ◽  
Before And After ◽  
C 30 ◽  
The Impact ◽  
Trial Performance

This study examined the impact of heat acclimation on improving exercise performance in cool and hot environments. Twelve trained cyclists performed tests of maximal aerobic power (V̇o2max), time-trial performance, and lactate threshold, in both cool [13°C, 30% relative humidity (RH)] and hot (38°C, 30% RH) environments before and after a 10-day heat acclimation (∼50% V̇o2max in 40°C) program. The hot and cool condition V̇o2max and lactate threshold tests were both preceded by either warm (41°C) water or thermoneutral (34°C) water immersion to induce hyperthermia (0.8–1.0°C) or sustain normothermia, respectively. Eight matched control subjects completed the same exercise tests in the same environments before and after 10 days of identical exercise in a cool (13°C) environment. Heat acclimation increased V̇o2max by 5% in cool (66.8 ± 2.1 vs. 70.2 ± 2.3 ml·kg−1·min−1, P = 0.004) and by 8% in hot (55.1 ± 2.5 vs. 59.6 ± 2.0 ml·kg−1·min−1, P = 0.007) conditions. Heat acclimation improved time-trial performance by 6% in cool (879.8 ± 48.5 vs. 934.7 ± 50.9 kJ, P = 0.005) and by 8% in hot (718.7 ± 42.3 vs. 776.2 ± 50.9 kJ, P = 0.014) conditions. Heat acclimation increased power output at lactate threshold by 5% in cool (3.88 ± 0.82 vs. 4.09 ± 0.76 W/kg, P = 0.002) and by 5% in hot (3.45 ± 0.80 vs. 3.60 ± 0.79 W/kg, P < 0.001) conditions. Heat acclimation increased plasma volume (6.5 ± 1.5%) and maximal cardiac output in cool and hot conditions (9.1 ± 3.4% and 4.5 ± 4.6%, respectively). The control group had no changes in V̇o2max, time-trial performance, lactate threshold, or any physiological parameters. These data demonstrate that heat acclimation improves aerobic exercise performance in temperate-cool conditions and provide the scientific basis for employing heat acclimation to augment physical training programs.

scholarly journals Effect of Heat and Heat Acclimatization on Cycling Time Trial Performance and Pacing

2015 ◽  
Vol 47 (3) ◽  
pp. 601-606 ◽  
Author(s):  
SEBASTIEN RACINAIS ◽  
JULIEN D. PÉRIARD ◽  
ANDERS KARLSEN ◽  
LARS NYBO
Keyword(s):  
Time Trial ◽  
Heat Acclimatization ◽  
Time Trial Performance ◽  
Cycling Time Trial ◽  
Cycling Time ◽  
Trial Performance

scholarly journals Lactate threshold predicting time-trial performance: impact of heat and acclimation

2011 ◽  
Vol 111 (1) ◽  
pp. 221-227 ◽  
Author(s):  
Santiago Lorenzo ◽  
Christopher T. Minson ◽  
Tony G. Babb ◽  
John R. Halliwill
Keyword(s):  
Exercise Performance ◽  
Lactate Threshold ◽  
Time Trial ◽  
Heat Acclimation ◽  
Mean Power ◽  
Performance Impact ◽  
Time Trial Performance ◽  
Threshold Test ◽  
Before And After ◽  
Trial Performance

The relationship between exercise performance and lactate and ventilatory thresholds under two distinct environmental conditions is unknown. We examined the relationships between six lactate threshold methods (blood- and ventilation-based) and exercise performance in cyclists in hot and cool environments. Twelve cyclists performed a lactate threshold test, a maximal O2 uptake (V̇o2max) test, and a 1-h time trial in hot (38°C) and cool (13°C) conditions, before and after heat acclimation. Eight control subjects completed the same tests before and after 10 days of identical exercise in a cool environment. The highest correlations were observed with the blood-based lactate indexes; however, even the indirect ventilation-based indexes were well correlated with mean power during the time trial. Averaged bias was 15.4 ± 3.6 W higher for the ventilation- than the blood-based measures ( P < 0.05). The bias of blood-based measures in the hot condition was increased: the time trial was overestimated by 37.7 ± 3.6 W compared with only 24.1 ± 3.2 W in the cool condition ( P < 0.05). Acclimation had no effect on the bias of the blood-based indexes ( P = 0.51) but exacerbated the overestimation by some ventilation-based indexes by an additional 34.5 ± 14.1 W ( P < 0.05). Blood-based methods to determine lactate threshold show less bias and smaller variance than ventilation-based methods when predicting time-trial performance in cool environments. Of the blood-based methods, the inflection point between steady-state lactate and rising lactate (INFL) was the best method to predict time-trial performance. Lastly, in the hot condition, ventilation-based predictions are less accurate after heat acclimation, while blood-based predictions remain valid in both environments after heat acclimation.

scholarly journals Impact Of Heat Acclimation On Steady-State Exercise And Time-Trial Performance In Hypobaric Hypoxia (3500m)

2020 ◽  
Vol 52 (7S) ◽  
pp. 190-190
Author(s):  
Beau R. Yurkevicius ◽  
Kirsten E. Coffman ◽  
Karleigh E. Bradbury ◽  
Adam J. Luippold ◽  
Katherine M. Mitchell ◽  
...  
Keyword(s):  
Steady State ◽  
Hypobaric Hypoxia ◽  
Time Trial ◽  
Heat Acclimation ◽  
Time Trial Performance ◽  
Trial Performance

scholarly journals Change in Exercise Performance and Markers of Acute Kidney Injury Following Heat Acclimation with Permissive Dehydration

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 841
Author(s):  
Arpie Haroutounian ◽  
Fabiano T. Amorim ◽  
Todd A. Astorino ◽  
Nazareth Khodiguian ◽  
Katharine M. Curtiss ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Kidney Injury ◽  
Time Trial ◽  
Heat Acclimation ◽  
Time Trial Performance ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Before And After ◽  
Temperate Environment ◽  
Kidney Injury Molecule 1 ◽  
Trial Performance

Implementing permissive dehydration (DEH) during short-term heat acclimation (HA) may accelerate adaptations to the heat. However, HA with DEH may augment risk for acute kidney injury (AKI). This study investigated the effect of HA with permissive DEH on time-trial performance and markers of AKI. Fourteen moderately trained men (age and VO2max = 25 ± 0.5 yr and 51.6 ± 1.8 mL.kg−1.min−1) were randomly assigned to DEH or euhydration (EUH). Time-trial performance and VO2max were assessed in a temperate environment before and after 7 d of HA. Heat acclimation consisted of 90 min of cycling in an environmental chamber (40 °C, 35% RH). Neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) were assessed pre- and post-exercise on day 1 and day 7 of HA. Following HA, VO2max did not change in either group (p = 0.099); however, time-trial performance significantly improved (3%, p < 0.01) with no difference between groups (p = 0.485). Compared to pre-exercise, NGAL was not significantly different following day 1 and 7 of HA (p = 0.113) with no difference between groups (p = 0.667). There was a significant increase in KIM-1 following day 1 and 7 of HA (p = 0.002) with no difference between groups (p = 0.307). Heat acclimation paired with permissive DEH does not amplify improvements in VO2max or time-trial performance in a temperate environment versus EUH and does not increase markers of AKI.

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