Cold baths and training: should you really plunge into ice water? Interview with Tom Normand-Gravier, PhD

Written by Marius Grek based on the interview, reviewed and approved by Tom Normand-Gravier.

In brief

Cold baths should be neither banned nor used systematically, since their value depends above all on the current goal, whereas heat, often overlooked, could prove to be a genuine performance tool. Figure 1 summarises how each can be used according to the training goal. In any case, these tools only provide a small extra benefit, which only makes sense once the basics are in place, namely regular training, sleep and nutrition.

Figure 1. Use of cold baths and heat according to the training goal.

Thermotherapy refers to the use of heat or cold as a tool to optimise athletes' performance and recovery. Cold is thought to limit muscle soreness and attenuate exercise-induced oxidative stress, whereas heat would act more on functional markers, such as the contractile capacity of muscle. Popularised from the 1990s and 2000s onwards, cold exposure quickly became widespread, from elite athletes to amateur and recreational sportspeople. While there is a consensus on its benefits for symptomatic recovery (delayed-onset muscle soreness, or DOMS), to which an improvement in sleep quality can be added, recent studies are far more nuanced regarding physiological recovery (oxidative stress and muscle adaptations). The nature of the intervention (heat or cold), its dose (duration, intensity and frequency) and its context of use (training vs competition) are all parameters to consider when establishing good practice.

Oxidative stress is not necessarily a form of cellular stress that must be reduced at all times: as a logical consequence of training, it is also necessary to induce the desired adaptations, particularly at the mitochondrial level (Vargas-Mendoza et al., 2021). Could cold then, by attenuating these signals, slow down training adaptations? This is what several recent studies on repeated cold exposure and skeletal muscle hypertrophy suggest.

It is in this context that the QNT team gave the floor to Tom Normand-Gravier, PhD in sport sciences, who specialises in thermal interventions and their impact on the adaptation and regeneration of skeletal muscle. Based on his interview with Marius Grek, nutrition specialist at QNT, this article covers the main questions discussed and attempts to separate myth from reality, in order to improve practices and guide athletes.

No stress, no progress: how training forces the body to adapt

Before discussing heat or cold, one prerequisite must be established: what allows athletes to progress is precisely what initially disrupts their balance.

Physiologically, physical exercise is a stress that disrupts the homeostasis of the cells involved, and it is this imbalance that triggers the adaptation signal. In the short term, each session triggers a cascade of transient molecular signals (acute response) arising from this disruption of homeostasis. In the long term, the repetition of these signals, session after session, results in so-called chronic adaptations, which are structural and lasting.

"Training induces stress, and stress induces adaptations. And the more trained you are, the harder it becomes to achieve new adaptations."

(Tom Normand-Gravier)

What the science says. The oxidative and inflammatory responses that follow exercise are not just collateral damage: they are among the molecular signals that drive muscle adaptation. Constantly attenuating them may limit the activation of these signalling pathways and therefore limit the physiological adaptations induced by training (Normand-Gravier et al., 2025b).

Practical implications. Performance results from the interaction of many factors (physiological, biomechanical, psychological, environmental). In beginners, the need for training specificity is low, almost any stimulus produces adaptations, and the key is to progress gradually to avoid injury. In experienced athletes, adaptations are harder to obtain, and it is the details that make the difference. This may ultimately be where strategies such as thermotherapy are most relevant.

Do cold baths slow down muscle gain?

This is probably the most interesting point of the discussion: is the belief that "cold bath = better recovery" being called into question?

While there is a consensus on the benefits of cold exposure for muscle soreness and sleep, current data show that it is important to consider the context in which it is used, so as not to risk hindering the physiological adaptations induced by training. In strength-trained athletes, repeated cold-water immersion over several weeks attenuates gains in hypertrophy and strength. In endurance athletes, however, cold does not seem to impair the desired adaptations, although it does not produce beneficial effects either. During training, constantly attenuating oxidative stress may prove counterproductive, since it is precisely one of the stresses one seeks to stimulate in order to adapt. Conversely, during the competition phase, where the priority is short-term performance rather than optimising training adaptations, cold exposure can be a useful strategy to reduce muscle soreness and certain inflammatory processes.

"You shouldn't systematically say 'no to cold, yes to heat'. It all depends on the athlete, their goal and the timing."

(Tom Normand-Gravier)

What the science says. In strength-trained individuals, repeated cold-water immersion after the session attenuates anabolic signalling (mTORC1 pathway), satellite cell activation and, ultimately, hypertrophy gains (Roberts et al., 2015; Fyfe et al., 2019). A recent cell study clarifies the mechanism: cold reduces mTORC1 pathway activity and protein synthesis in a cell-autonomous manner, independently of the AMPK pathway (Sung et al., 2026). In endurance athletes, however, hypertrophy and mTORC1 activation are not among the desired adaptations, while those that are, such as mitochondrial biogenesis or angiogenesis, do not appear to be affected by cold (Normand-Gravier et al., 2025b).

Figure 2. Cold baths attenuate the muscle's building signal (anabolic signal) (mTORC1 pathway, satellite cell activation), which attenuates muscle mass gain.

Practical implications. During a strength or mass-building phase, it would probably be beneficial to wait a few hours after resistance training before taking a cold bath (unless there is a need to keep going despite marked muscle soreness). In endurance sports, or in the run-up to a competition, cold appears on the other hand to be usable without reservation, for sleep as well as for comfort.

Cold or heat: two different types of recovery

Cold and heat do not act on the same levers, so they must be distinguished in order not to hinder physiological adaptations.

Two types of recovery can be distinguished. The first, symptomatic, relates to how one feels, with less muscle soreness, an effect that is partly psychological and placebo. It is on this type of recovery that cold has a favourable effect, in addition to its effect on sleep. The second, functional, is measured on objective physiological markers (notably the contractile capacity of muscle and rapid force production, or RFD). This is rather where heat comes into play.

What about alternating heat and cold, so widespread today? There is still a lack of hindsight: studies are scarce, some signals appear favourable (for example in martial arts practitioners), but nothing yet allows a firm recommendation to be made.

"Cold is rather a symptomatic recovery. Heat, on the other hand, is rather functional: it acts on objective physiological markers."

(Tom Normand-Gravier)

What the science says. Cold mainly targets muscle soreness and sleep quality, at the cost of an attenuated hypertrophic response after strength training; heat acts more on objective physiological markers, notably the ability to produce force rapidly (RFD) and maximal concentric strength (Sautillet et al., 2024). As for alternating heat and cold, it remains an emerging field of research, with no firm conclusion to date (Normand-Gravier et al., 2025b).

Practical implications. Rather than choosing between cold and heat "in general", it would be worth asking what the athlete needs and for which current goal.

Training in the heat: a new performance tool?

Used well, heat does not just improve recovery, it can also improve performance.

As mentioned above, physical exercise is a stress to which the body must adapt, and attenuating it can have a detrimental effect on these adaptations. What happens, then, if this stress is deliberately increased? Long used by elite athletes, altitude training camps increase haemoglobin mass and therefore improve performance at sea level through an improvement in maximal oxygen uptake (VO₂max). The same principle seems to apply to the use of heat during training. With repeated heat exposure over several weeks, the body adapts, notably by learning to better regulate its core temperature during exercise through increased sweating. In the long term, heat exposure during training sessions also promotes an increase in plasma volume and haemoglobin mass (with the effect of increasing VO₂max). Training in summer can thus produce adaptations comparable to those of an altitude camp, leading to better performance later in temperate or cold environments.

"Heat exposure has really become a performance optimisation tool. I wouldn't be surprised if it were soon used like altitude."

(Tom Normand-Gravier)

What the science says. Heat acclimation increases plasma volume and improves VO₂max, including in temperate conditions (Lorenzo et al., 2010), and prolonged passive exposure (hot baths over five weeks) also increases haemoglobin mass in trained runners (Jenkins et al., 2025). At the cellular level, heat can also act as an "exercise mimetic" and help preserve muscle mass during immobilisation (Normand-Gravier et al., 2025b); its effects on muscle protein synthesis and autophagy, particularly during recovery after immobilisation, are the subject of recent animal studies (Normand-Gravier et al., 2025a, 2026).

Practical implications. Heat has a considerable effect on performance: when it is hot, the heart beats faster and dehydration occurs more quickly. Rather than bringing the programme to a halt, it is advisable to adapt sessions by reducing intensity and volume before gradually increasing them as acclimation progresses.

Heat or cold: one more tool, not a miracle recipe

One simple idea emerges from this discussion: when it comes to thermotherapy, there is no universal rule. Everything depends on three parameters, namely the nature of the intervention (heat or cold), its dose (the intensity and duration of each exposure, as well as their frequency, in sessions per week as well as in number of weeks) and its context (the type of training and the time of the season). Cold relieves muscle soreness and promotes sleep, but it can hold back adaptations when the goal is to build muscle, precisely because it attenuates the stress that triggers them. Heat follows the opposite path: functional recovery on the one hand and, above all, a genuine performance lever on the other, capable, through acclimation, of producing adaptations similar to those obtained at altitude.

Tom Normand-Gravier points out that these techniques only produce marginal gains, which only make sense once the fundamentals are in place, namely consistent training, regularity, sleep and appropriate nutrition. Used well, thermotherapy refines performance; applied indiscriminately, following trends, it risks undermining it. The real question is therefore not finding the miracle technique, but knowing, each time, for which goal, at what dose and at what point in the season it is used.

By Marius Grek, nutrition expert at QNT Sport.

References

Douzi, W., Dupuy, O., Theurot, D., Boucard, G., & Dugué, B. (2019). Partial-body cryostimulation after training improves sleep quality in professional soccer players. BMC Research Notes, 12, 141. https://doi.org/10.1186/s13104-019-4172-9

Fyfe, J. J., Broatch, J. R., Trewin, A. J., Hanson, E. D., Argus, C. K., Garnham, A. P., Halson, S. L., Polman, R. C., Bishop, D. J., & Petersen, A. C. (2019). Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. Journal of Applied Physiology, 127(5), 1403‑1418. https://doi.org/10.1152/japplphysiol.00127.2019

Jenkins, E. J., Killick, J. A., Zerilli, O., Douglas, A. J. M., Corr, L., Hughes, M. G., Tremblay, J. C., & Stembridge, M. (2025). Long-term passive heat acclimation enhances maximal oxygen consumption via haematological and cardiac adaptation in endurance runners. The Journal of Physiology. Advance online publication. https://doi.org/10.1113/JP289874

Lorenzo, S., Halliwill, J. R., Sawka, M. N., & Minson, C. T. (2010). Heat acclimation improves exercise performance. Journal of Applied Physiology, 109(4), 1140‑1147. https://doi.org/10.1152/japplphysiol.00495.2010

Normand-Gravier, T., Solsona, R., Arnould, F., Deriaz, R., Bertrand-Gaday, C., Borrani, F., Bernardi, H., & Sanchez, A. M. J. (2025a). Acute effects of heat intervention and hybrid exercise on protein synthesis, ribosome biogenesis and autophagy. Journal of Thermal Biology, 131, 104169.

Normand-Gravier, T., Solsona, R., Dablainville, V., Racinais, S., Borrani, F., Bernardi, H., & Sanchez, A. M. J. (2025b). Effects of thermal interventions on skeletal muscle adaptations and regeneration: Perspectives on epigenetics: A narrative review. European Journal of Applied Physiology, 125(2), 277‑301. https://doi.org/10.1007/s00421-024-05642-9

Normand-Gravier, T., Solsona, R., Bertrand-Gaday, C., Issertine, M., Sabatier, F., Arnould, F., Racinais, S., Borrani, F., Bernardi, H., & Sanchez, A. M. J. (2026). Heat treatment combined with hybrid exercises retraining mitigates cellular markers of protein turnover after hindlimb suspension in male mice: A pilot study. Experimental Physiology. Advance online publication. https://doi.org/10.1113/EP093111

Roberts, L. A., Raastad, T., Markworth, J. F., Figueiredo, V. C., Egner, I. M., Shield, A., Cameron-Smith, D., Coombes, J. S., & Peake, J. M. (2015). Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology, 593(18), 4285‑4301. https://doi.org/10.1113/JP270570

Sautillet, B., Bourdillon, N., Millet, G. P., Lemaître, F., Cozette, M., Delanaud, S., Ahmaïdi, S., & Costalat, G. (2024). Hot water immersion: Maintaining core body temperature above 38.5°C mitigates muscle fatigue. Scandinavian Journal of Medicine & Science in Sports, 34(1), e14503. https://doi.org/10.1111/sms.14503

Sung, B. Y., Ford, E. J., Foster, D. J., Fullmer, K. J., Cromwell, C., Viollet, B., & Thomson, D. M. (2026). Acute cold exposure cell-autonomously reduces mTORC1 signaling and protein synthesis independent of AMPK. Cells, 15(1), 65. https://doi.org/10.3390/cells15010065

Vargas-Mendoza, N., Angeles-Valencia, M., Morales-González, Á., Madrigal-Santillán, E. O., Morales-Martínez, M., Madrigal-Bujaidar, E., Álvarez-González, I., Gutiérrez-Salinas, J., Esquivel-Chirino, C., Chamorro-Cevallos, G., Cristóbal-Luna, J. M., & Morales-González, J. A. (2021). Oxidative stress, mitochondrial function and adaptation to exercise: New perspectives in nutrition. Life, 11(11), 1269. https://doi.org/10.3390/life11111269