Vpliv vročega okolja na maksimalni privzem kisika, frekvenco srca ter jedrno in kožno temperaturo med kolesarjenjem : magistrsko delo

Bajt, Ambrož (author), Verdel, Nina (mentor), Supej, Matej (comentor)

Namen magistrskega dela je bil preučiti vpliv vročega okolja na fiziološke odzive telesa med kolesarjenjem. Osredotočili smo se na maksimalni privzem kisika (V̇O₂ max), frekvenco srca, jedrno temperaturo in temperaturo kože. V raziskavi je sodelovalo devet zelo dobro treniranih moških kolesarjev (starost 28,2 ± 4,3 leta; telesna masa 73,1 ± 5,8 kg; telesna višina 181,3 ± 6,2 cm), ki so opravili stopnjevane obremenitvene teste do odpovedi v dveh različnih okoljskih pogojih: pri 17 °C in 70 % relativni vlažnosti (zmerno okolje) ter pri 35 °C in 50 % relativni vlažnosti (vroče okolje). Meritve so potekale v okoljski komori na cikloergometru, pri čemer smo porabo kisika spremljali s sistemom Cosmed K5, frekvenco srca s senzorjem Polar H10, temperaturo jedra z gastrointestinalno kapsulo e-Celsius ter temperaturo kože s senzorji iButton. Vsak merjenec je opravil oba testa v naključnem vrstnem redu z vsaj 48-urnim razmikom med preizkusoma. Protokol je vključeval stopnjevano obremenitev do odpovedi z začetno obremenitvijo 100 W in povečevanjem za 20 W vsako minuto. Za obdelavo podatkov smo uporabili programa Microsoft Excel in MATLAB. Rezultati so pokazali, da se je V̇O₂ pri obremenitvah 180 W in 220 W v vročem okolju statistično značilno zvišal (p = 0,001; p = 0,003), ni pa bilo značilnih razlik v V̇O₂ max (p = 0,08). Frekvenca srca je bila v vročem okolju statistično značilno višja pri skoraj vseh obremenitvah (p < 0,001), izjema sta bili le začetna in maksimalna vrednost. Povprečna jedrna temperatura je bila v vročem okolju višja, vendar razlika ni bila statistično značilna (p > 0,1), enako velja za temperaturo jedra ob maksimalni obremenitvi. Temperatura kože pa je bila v vročem okolju značilno višja pri vseh obremenitvah, vključno z odpovedjo (p < 0,0001). Ugotovili smo, da vroče okolje pomembno vpliva na fiziološke odzive med kolesarsko obremenitvijo, predvsem na frekvenco srca in temperaturo kože. Submaksimalni V̇O₂ se je znižal, medtem ko na V̇O₂ max in jedrno temperaturo krajša izpostavljenost vročini ni imela značilnega vpliva. Rezultati poudarjajo pomen priprave športnikov na vadbo v vročini z aklimatizacijo in ustreznimi strategijami hlajenja.

• Language: Slovenian
• Keywords: vročina, maksimalni privzem kisika, frekvenca srca, temperatura jedra, kolesarjenje
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FŠ - Faculty of Sport
• Year: 2025
• PID: 20.500.12556/RUL-170233
• COBISS.SI-ID: 249684995
• Publication date in RUL: 02.07.2025

Secondary language

• Language: English
• Title: The Influence of a Hot Environment on Maximum Oxygen Uptake, Heart Rate and Core and Skin Temperature During Cycling

Abstract

The present master's thesis aimed to examine the influence of a hot environment on the body's physiological responses during cycling. We focused on maximal oxygen uptake (V̇O₂ max), heart rate, core temperature, and skin temperature. The study included nine highly trained male cyclists (age 28.2 ± 4.3 years; body mass 73.1 ± 5.8 kg; height 181.3 ± 6.2 cm), who underwent graded exercise tests to exhaustion in two different environmental conditions: 17 °C with 70 % relative humidity (moderate environment) and 35 °C with 50 % relative humidity (hot environment). Measurements were conducted in a climate chamber using a cycle ergometer. Oxygen consumption was measured with the Cosmed K5 portable system, heart rate was monitored using the Polar H10 sensor, core temperature was recorded with the e-Celsius gastrointestinal capsule, and skin temperature was measured with iButton sensors. Each participant completed both tests in a randomised order with at least 48 hours between sessions. The protocol involved a progressive workload to exhaustion, starting at 100 W with increments of 20 W every minute. Data analysis was performed using Microsoft Excel and MATLAB. Results indicated that V̇O₂ at 180 W and 220 W was significantly higher in the hot environment (p = 0.001; p = 0.003), while no statistically significant difference was observed in V̇O₂ max (p = 0.08). Heart rate was significantly elevated in the hot environment at nearly all workloads (p < 0.001), except during the initial stage and at maximal value. Average core temperature was higher in the hot environment, although this difference was not statistically significant (p > 0.1), nor was the difference noted at exhaustion. Conversely, skin temperature was significantly higher at all workloads in the hot environment, including at exhaustion (p < 0.0001). We found that a hot environment significantly affects physiological responses during cycling, particularly heart rate and skin temperature. Submaximal V̇O₂ decreased, while acute heat exposure had no significant effect on V̇O₂ max or core temperature. These findings highlight the importance of athlete preparation for exercising in the heat through acclimatisation and suitable cooling strategies.

• Keywords: heat, maximal oxygen uptake, heart rate, core temperature, cycling