Respiratory Function and Symptoms Post Cold Air Exercise in Female High and Low Ventilation Sport Athletes

Abstract

Purpose: Cold weather exercise is common in many regions of the world; however, it is unclear whether respiratory function and symptom worsen progressively with colder air temperatures. Furthermore, it is unclear whether high-ventilation sport background exacerbates dysfunction and symptoms.

Methods: Seventeen active females (measure of the maximum volume of oxygen [VO(2max)]: 49.6±6.6 mL·kg⁻¹·min⁻¹) completed on different days in random order 5 blinded running trials at 0°C, -5°C, -10°C, -15°C, and -20°C (humidity 40%) in an environmental chamber. Distance, heart rate, and rating of perceived exertion (RPE) were measured within each trial; forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow at 25%-75% (FEF₂₅₋₇₅), and forced expiratory flow at 50% (FEF₅₀) were measured pre- and post-test (3, 6, 10, 15, and 20 minutes). Respiratory symptoms and global effort were measured post-test spirometry.

Results: Mean decreases were found in FEV1 (4%-5% at 0°C, -5°C, -10°C, and -15°C; 7% at -20°C). FEF₂₅₋₇₅ and FEF₅₀ decreased 7% and 11% at -15°C and -20°C, respectively. Post-exertion spirometry results were decreased most at 3 to 6 minutes, recovering back to baseline at 20 minutes. Respiratory symptoms and global effort significantly increased at -15°C and -20°C with decreased heart rate. High-ventilation sports decreased function more than low-ventilation participants but had fewer symptoms.

Conclusions: These results indicate that intense exercise at cold air temperatures up to -20°C is achievable; however, greater effort along with transient acute bronchoconstriction and symptoms of cough after exercising in temperatures colder than -15°C are likely. It is recommended that individuals cover their mouth and reduce exercise intensity to ameliorate the effects of cold weather exercise.

Keywords: Exercise-induced asthma; cold climate; cough; exercise-induced bronchospasm; extreme environments; spirometry.

Fig. 1. Delta maximum decrease for FEV1 (A), FVC (B), FEF_25-75 (C), and FEF₅₀ (D) at GXT (ambient laboratory temperature 23℃; relative humidity 50%), 0℃, -5℃, -10℃, -15℃, and -20℃ (relative humidity 40%). FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; FEF_25-75, forced expiratory flow at 25%-75%; FEF₅₀, forced expiratory flow at 50%; GXT, graded exercise test.

Fig. 2. Delta change for FEV1 at each time point at each temperature condition expressed as percent change from pre-test baseline. Results are mean±SD (n=17) and significance was set at P<0.05. FEV1, forced expiratory volume in 1 second; SD, standard deviation. A, 3 minutes 0℃ and -20℃ diff; B, -10℃ and -20℃ diff (P<0.05); GXT=0.01, pairwise comparisons with differences as follows. ^*3 minutes diff than 10, 15, 20 minutes, ^‡20 minutes diff than 6, 10 and 15 minutes; 0℃=0.01, pairwise comparisons with differences as follows; ^β20 minutes diff than 3 and 6 minutes; -5℃=0.08, pairwise comparisons with differences as follows; ^*3 diff than 20 minutes; ^α6 minutes diff than 15 and 20 minutes; -10℃=0.00, pairwise comparisons with differences as follows: ^Δ3, 6, and 10 minutes diff than 15 and 20 minutes; -15℃=0.00, pairwise comparisons with differences as follows: ^Ω3 minutes diff than 6, 15, and 20 minutes; ^µ20 minutes diff 15, 10, and 6 minutes; -20℃=0.03, pairwise comparisons with differences as follows: ^¥3 minutes diff than 10 and 20 minutes; ^£6 minutes and 20 minutes diff.