Sauna for Endurance: What Heat Training Can Do for Your Next Race

For most of us, the sauna is where a hard week ends: ten quiet minutes, a towel over your head, and the feeling of tight muscles finally letting go.

For endurance athletes, it can be more than that. Used regularly after training, heat exposure triggers some of the same changes your body makes when it gets used to running in the heat. Here is what the research shows, how big the studies really were, and how to build sauna sessions into your training.

Sauna Training at a Glance

Why Heat Helps an Endurance Engine

When you get used to heat, your body adapts in several ways. A 2015 review of heat acclimation in Scandinavian Journal of Medicine and Science in Sports lists them:

• Better Sweating: You sweat more effectively and your skin blood flow improves.
• A Cooler Core: Body temperature runs lower for the same effort, and your heart works less hard.
• Better Fluid Balance: Your body handles fluid better, including a bigger plasma volume.
• Faster in the Heat: Aerobic performance improves in warm and hot conditions, and possibly in cooler ones too.

Plasma volume is the change the sauna studies measured. In the 2007 runner study, each runner's improvement tracked closely with how much their plasma and total blood volume went up, and the authors concluded the gain probably came from that extra blood volume.

Six runners, three weeks, 32% longer to exhaustion. Small study, big effect.

How Big Is the Effect, Really?

A 32% longer run to exhaustion sounds huge, but it is not the same as racing 32% faster. The authors of the 2007 study worked out that it was equivalent to roughly a 1.9% improvement in an endurance time trial. The authors still called it a worthwhile enhancement of endurance running performance.

The bigger caution is sample size. These were studies of six and seven athletes, all men. They point in a promising direction, but they are not the final word.

How to Build a Sauna Routine

• Go After Training: Both studies used the sauna straight after a normal training session, not on its own.
• Start Shorter: The studies used about 30 minutes. Shelter's own guide suggests 5 to 15 minutes in the heat per round, which is a sensible place to begin before you build up.
• Know the Temperature: Shelter's hot sauna runs at 70 to 90°C, the same range as the studies.
• Be Consistent: In the cycling study, plasma volume peaked after just four sessions, so a few sessions a week across a block is enough to try it.

Photo: SportPlus.sg / Aldrich Goh

Hydration and Safety

You are deliberately adding heat stress, so fluids are part of the session, not an afterthought.

• Weigh Yourself: The same before-and-after weigh-in you use for running works here. Our sweat rate guide shows you how.
• Replace Sodium: Sweat takes sodium with it. Our guide to electrolytes explains how much.
• Listen to the Warning Signs: Shelter's sign warns that prolonged exposure to heat and cold can lead to dehydration, dizziness and nausea. If you feel any of them, get out, cool down and tell the staff.
• Check First: If you have a heart condition, high blood pressure or are pregnant, speak to your doctor before you start.

Use the Sauna at Shelter on ATHLO+

Shelter is a recovery club built around sauna and ice baths at 1 Raffles Link #01-01, open daily from 7am to 10pm. Whether you need to book depends on your membership or pass, so message Shelter and they will point you to the right option.

Ready to add the cold as well? Read our guide to contrast therapy next.