Cold or Warm – What Gives You the Biggest Wellness Bang for the Buck?

Cold and heat exposure are widely used methods to support recovery, stress management, and overall wellbeing. This blog contrasts some of the benefits of exposure to cold elements, such as ice plunging, with heat-based practices, such as sauna or warm baths, discussing how they impact the body and when and why they might be most effective.

Are you someone who takes a cold shower every morning, dips into an icy lake whenever possible, or steps into an ice bath to boost resilience and recovery?

Or are you more inclined to enjoy the soft heat of a Finnish sauna, a steam room, or a warm bubble bath to help you (and your muscles) relax and unwind?

I get asked about the benefits of cold versus heat exposure quite often – “what’s better for my HRV or recovery”? In this blog, I’ll focus on whole-body exposure to the element of cold versus warm (rather than topical use of ice or heat), looking at a few research findings but mainly personal experiences and based on discussions with clients. Both cold and warm exposure can support different aspects of wellbeing, but in somewhat different ways. Based on research, one doesn’t seem to be universally “better” than the other. The best choice depends on your goal, time of day, and health status (for example, ice plunging is not recommended for those with certain lung or heart conditions) – and on personal preference!

Is ice dipping for me?

If the idea of a cold plunge sounds terrible, or leaves you shivering for hours afterwards, you are probably better off finding a different way to boost your energy or get relief for sore muscles. We all have so many things that we “must do”, whether we like them or not (chores, deadlines, or certain aspects of wellness …), that adding a trendy wellness hack such as ice plunging to your routine doesn’t make sense if it disagrees with you. If you are basically healthy and follow sensible guidelines, it’s not going to hurt you, but there doesn’t seem to be conclusive proof that ice baths are a universal game changer, offering major health or wellness benefits in the long term. Many believe that an ice bath will help you if you believe that it helps you, which probably explains why so many athletes spend time in ice baths after their workout – and that can sometimes be all the reason that one needs! I’m not saying cold plunges are not good for you; simply pointing out that proof of their health benefits is somewhat contested, or at least situational and individual.

What about heat?

There are studies that suggest warm baths to be beneficial for recovery and sleep – and regular sauna sessions have even been found to be positively associated with cardiorespiratory health benefits (reference to a large Finnish longitudinal study below). The gentle exposure to heat can help the muscles relax and the pleasant overall sensation can help both the mind and the body start recovering. But this is also a matter of personal preference – finding the recovery method that works and is available for you.

Slightly different benefits

In principle, a cold plunge might be better for an acute energy boost, post-exercise soreness, and mental toughness / resilience, whereas a warm bath or sauna is more likely to promote stress reduction, relaxation or sleep, and mental calmness. Perhaps cold treatment is more suited for earlier in the day (for the energy boost), whereas warmth can be best suited for the evening, to boost relaxation before sleep.

My experiences

If I seemed to question the benefits of cold exposure, I should mention that I do several versions of it myself… I end my morning shower with a cold rinse all over my body, for an energizing effect, and I aim to take a dip in icy water once per week throughout the winter. When the conditions are right, I’m even no stranger to rolling in fresh snow between my sauna sessions! I admit that the thought of going ice swimming on a cold day is not always tempting, and I do get cold when I’m in. I don’t stay for several minutes; typically, I slowly count to 10 or 20 and when I start feeling cold, I come out. It energizes me and I feel that it boosts my “toughness” / resilience during the harsh winter months. Some studies have also reported that cold exposure boosts HRV and vagal activity, and since I’m genetically prone to low HRV, I’m hoping to see some benefits in this area. So far, I’ve not seen any systematic change, but the experiment is ongoing…

I can definitely vouch for the mental benefits of both cold and warm exposure! I feel mentally sharp and energized after taking a cold shower or an ice dip and pleasantly relaxed after a warm bath or a soothing sauna. Both habits can be a nice way to break away from the daily routine, while stimulating or calming down the nervous system at the same time.

If you are keen to learn more about the potential benefits, this is a fascinating area to experiment on. Including some wearable data in your experimentation adds an interesting angle to testing – do you see a bit more recovery or higher HRV on the days when you take a cold plunge or is your sleep better after a warm bath or sauna? I’d love to hear what works for you!

Figure 1 shows one example from Firstbeat Life data, illustrating the effect of a relaxing sauna after a busy day. Right after the sauna, the body’s activation level and heart rate is elevated, which is very natural considering the earlier physical effort and the elevated heart rate that heat acutely causes, but after a short while, the nervous system relaxes and this person enjoys a very restorative sleep. I’ve seen similar results in my own experimentations, as long as the sauna is not too late in the evening (and preferably only includes a non-alcoholic beer…).

Fig. 1. Busy afternoon, followed by a relaxing sauna (pink area; device off) and excellent recovery during sleep.

For context and background, here are a few links to interesting articles and research reviews that touch on this topic and highlight both possible benefits and risks:

https://www.bbc.com/future/article/20250520-are-saunas-and-cold-plunges-good-for-your-health.

https://www.health.harvard.edu/heart-health/cold-plunges-healthy-or-harmful-for-your-heart.

https://journals.lww.com/jcrjournal/abstract/2024/07000/enhancing_cardiorespiratory_fitness_through_sauna.11.aspx.

https://www.medicalnewstoday.com/articles/29108.

Firstbeat Life Makes Stress Personal

Firstbeat Life is a heart rate variability -based measurement, conducted in a person’s daily life over several days, focused on identifying excessive stress and seeing if recovery mechanisms are working to counterbalance the stress. The value of using this kind of objective real-life data in coaching programs is powerful because it helps the coach and the client see how the body is reacting to life – identifying strengths as well as challenge areas. Getting a visual on the person’s stress profile and putting it in context of their life situation and how they are feeling makes it possible to build realistic and personalized strategies to tackle stress and prevent it from building up, instead of having to rely on often unrealistic one-size-fits-all solutions.