Running in the summer sun? Have a hot bath first, researchers say

A long soak in a hot bath is the best way to prepare to exercise in the summer heat, according to a new study published in the Journal of Strength and Conditioning Research.

Scientists from the University of Brighton performed tests on nine recreational runners (eight men and one woman) in a climate-controlled room.

They were observed while they ran on a treadmill at top speed in temperatures exceeding 32 degrees Celsius.

The slowest times were recorded on the first five kilometre run, with no preparations made for the heat. On the second run the volunteers ‘precooled’ using underwear fitted with ice packs, which increased their speed by an average of four per cent. The most effective method was heat acclimation, which reduced average running time by 6.5 per cent.

To acclimatise, the volunteers pedalled an exercise bicycle for about 90 minutes in temperatures of 37 degrees Celsius. They did this on five consecutive days before running.

Carl James, the study’s lead author, says the results show that you will receive a ‘bigger bang for your buck’ from acclimating to the heat rather than by temporarily cooling using icepacks.

He recommends that, to start with, you should exercise at a gentler pace than normal when it’s hot. For optimal results he suggests a 30-minute bath, heated to 40 degrees Celsius, taken before a 30-minute run.