Rain affects performance in the cold

Introduction
Environmental factors such as heat and cold, humidity, wind and altitude influence the performance of athletes young and old, especially endurance athletes. While their have been plenty of studies examining the effects of these factors on performance, little research has ever been done to examine the effects of rain on performance, especially in the cold. The present study aimed to determine energy metabolism while running in cold, wet conditions using a climatic chamber that precisely simulated rainy conditions.

The Research

Seven healthy (trained 3 times per week) men (23.3 ± 2.9 years; 168.6 ± 7.5 cm; 65.9 ± 8.1 kg; VO2max 52.0 ± 5.7 mL/kg/min) ran on a treadmill at 70 % VO2 (about 82% max heart rate) intensity for 30 min in a climatic chamber at an air temperature of 5°Celsius in the presence or absence of 40 mm/hr of very heavy rain. Expired air, oxygen consumption, oesophageal (down the throat and into the gut) temperature, heart rate, skin temperature, rating of perceived exertion and blood samples (lactate, glucose, adrenalin [stress hormone] and noradrenalin [increases heart rate]) were measured before the 30 min run and every 10 minutes of the 30 min test.

The Results

Oesophageal (body) temperature and average skin temperature were significantly lower in the rain condition than in the non-rain run. The amount of air breathed per minute, oxygen consumption used during the run, and levels of blood lactate and noradrenalin were significantly higher in rain. In conclusion, the higher oxygen consumption and plasma lactate in rain indicated that energy demand increases when running in cold and wet conditions.

So What?

This study is one of the first to suggest that rain has a strong effect on endurance performance, especially in the cold. The higher blood lactate, higher oxygen consumption and ventilation volumes all suggest that glycogen energy stores will be used up more quickly too. This suggests making sure that if we race or train hard in the cold (and wet), that we carbohydrate load well before training or racing, replace carbs during longer (> one hour) training and racing, and ensure we replace carbs more aggressively after training and racing to recover.

For more specific ‘bridging the gap’ tips on training in the cold or heat see chapter 11 of my book The Masters Athlete. For more on carbohydrates before, during and after training or racing, see chapter 16 of The Masters Athlete.

Source: Ito, R. and others (2013) Effects of rain on energy metabolism while running in a cod environment. International Journal of Sports Medicine, 34(8): 707-711.