In this study, thermal behaviours of the athletes were investigated with respect to thermal comfort and exercise intensity. The relationship between an index for analysing thermal comfort (Predicted Mean Vote: PMV) and Rating of Perceived Exertion (RPE) which shows exercise intensity and exhaustion level was evaluated. Eleven moderately trained male athletes ( $\dot{\mathrm{V}}$ O_2max 54 ± 9.9 mL∙min⁻¹∙kg⁻¹) had volunteered for the study (age: 22.2 ± 3.7 years; body mass: 73.8 ± 6.9 kg; height: 181 ± 6.3 cm; Body surface area (BSA): 1.93 ± 0.1 m²; body fat: 12.6% ± 4.2%; $\dot{\mathrm{V}}$ O_2max: 54 ± 9.9 mL∙min⁻¹∙kg⁻¹). Experiments were carried out by using a cycle ergometer in an air-conditioned test chamber which provided fresh air and had the ability to control the temperature and relative humidity. The study cohort was divided into two groups according to maximal oxygen consumption levels of the participants. Statistical analyses were conducted with the whole study cohort as well as the two separated groups. There was a moderate correlation between PMV and RPE for whole cohort (r: −0.51). When the whole cohort divided as low and high aerobic power groups, an average correlation coefficient at high oxygen consumption cohort decreased to r: −0.21, while the average correlation coefficient at low oxygen consumption cohort increased to r: −0.77. In conclusion, PMV and RPE have a high correlation in less trained participants, but not in the more trained ones. The case may bring to mind that thermal distribution may be better in high aerobic power group in spite of high RPE and thus the relation between PMV and RPE is affected by exercise performance status.

The purpose of this study was to evaluate whether greater and sustainable stroke volume (SV) responses may be obtained by exercise intensities corresponding to peak SV (SV_peak) vs. maximal O₂ consumption ( ), and short vs. long intervals (SI vs. LI). Nine moderate- to well-trained male athletes competing at regional level specialists of cyclist, track and field volunteered to take part in the study ( : 59.7 ± 7.4 mL·min⁻¹·kg⁻¹). Following familiarisation sessions, was determined, and then SV_peak was evaluated using exercise intensities at 40%–100% of by nitrous-oxide rebreathing (N₂O_RB) method. Then each separate participant exercised wattages corresponding to individual and SV_peak during both SI (SI and SI_SVpeak) and LI (LI and LI_SVpeak) workouts on a cycle ergometer. Main results showed that both SI and SI_SVpeak yielded greater SV responses than LI and LI_SVpeak (p ≤ 0.05). Mean SV responses were greater in LI_SVpeak than in LI (p ≤ 0.05), but there was no statistical difference between SI_SVpeak and SI . However, there was significantly less physiological stress based on VO₂, respiratory exchange ratio, heart rate and rate of perceived exhaustion in SV_peak than in intensities (p ≤ 0.05). Moreover, SV responses at exercise phases increased in the early stages and remain stable until the end of SI and SI_SVpeak workouts (p > 0.05), while they were gradually decreasing in LI and LI_SVpeak sessions (p ≤ 0.05). In conclusion, if the aim of a training session is to improve SV_peak with less physiological stress, SI_SVpeak seems a better alternative than other modalities tested in the present study.

BACKGROUND: Although several studies have focused on maximal O₂ uptake ([ ] O_2max) measured by a verification phase following the determination of peak O₂ uptake ([ ] O_2peak) by a graded exercise test, an explanation for the underlying mechanisms of the difference between[ ] O_2peak and confirmed [ ] O_2max is scant. OBJECTIVE: To explore the hypothesis that when the difference between [ ] O_2peak and [ ] O_2max(Δ[ ] O₂) increases, the gap between peak stroke volume (SV_peak) and SV level corresponding to [ ] O_2peak velocities (Δ SV) grows. METHODS: Nine moderately to well-trained male athletes([ ] O_2max: 60.2 ± 7 mL ⋅ min^-1 ⋅ kg^-1) volunteered to take part in the study. Following familiarization session, volunteers were asked to perform submaximal and maximal graded exercise tests. Then, constant-loading SV_peak tests (using wattages in a range from 40-100% of [ ] O_2peak) and verification phase (using wattages corresponding with 100-110% of [ ] O_2peak) were conducted in a climatic chamber. RESULTS: The Δ[ ] O₂ was well correlated withΔ SV (Pearson r= 0.89; p≤ 0.001). The mean SV_peak of participants corresponded to 60.3 ± 18% of [ ] O_2peak.[ ] O_2max was significantly greater (11.2%) than [ ] O_2peak (60.2 ± 7 vs. 54.2 ± 8.1 mL ⋅ min^-1 ⋅ kg^-1) (p ≤ 0.01). CONCLUSIONS: [ ] O_2peak and [ ] O_2max differences may be related to the gap between SV_peak and SV at [ ] O_2peak.

Cardiovascular drift (CV-Drift) may occur after the ~10th min of submaximal continuous exercising. The purpose of this study was to examine whether CV-Drift is prevented by an intermittent exercise modality, instead of a continuous exercise. Seven well-trained male cyclists volunteered to take part in the study ( $\dot{\mathrm{V}}$ O_2max: 61.7 ± 6.13 mL·min⁻¹·kg⁻¹). Following familiarization sessions, athletes’ individual maximal O₂ consumption ( $\dot{\mathrm{V}}$ O_2max), maximum stroke volume responses (SV_max), and cardiac outputs (Qc) were evaluated by a nitrous-oxide re-breathing system and its gas analyzer. Then, continuous exercises were performed 30 min at cyclists’ 60% $\dot{\mathrm{V}}$ O_2max, while intermittent exercises consisted of three 10 min with 1:0.5 workout/recovery ratios at the same intensity. Qc measurements were taken at the 5th, 9th, 12nd, 15th, 20th, 25th, and 30th min of continuous exercises versus 5th and 10th min of workout phases of intermittent exercise modality. Greater than a 5% SV decrement, with accompanying HR, increase, while Qc remained stable and was accepted as CV-Drift criterion. It was demonstrated that there were greater SV responses throughout intermittent exercises when compared to continuous exercises (138.9 ± 17.9 vs. 144.5 ± 14.6 mL, respectively; p ≤ 0.05) and less HR responses (140.1 ± 14.8 vs. 135.2 ± 11.6 bpm, respectively; p ≤ 0.05), while mean Qc responses were similar (19.4 ± 2.1 vs. 19.4 ± 1.5 L, respectively; p > 0.05). Moreover, the mean times spent at peak SV scores of exercise sessions were greater during intermittent exercise (1.5 vs. 10 min) (p < 0.001). In conclusion, intermittent exercises reduce CV-Drift risk and increases cardiac adaptation potentials of exercises with less physiological stress.