Ice baths have gained more popularity recently due to its reported physiological and psychological benefits, such as improving mood, energisation, optimism, well-being, and lowering heart rate, thought to originate from the mammalian dive reflex (Carona and Marques, 2023). Furthermore, cold water activates the sympathetic autonomic nervous system, triggering beta-endorphin and noradrenaline in the blood (Carona & Marques, 2023). Moreover, CWI is likely to send a huge number of electrical impulses from nerve endings in the skin to the brain, which may provide an antidepressant effect similar to ECT (Carona and Marques, 2023).
A further mechanism that CWI may stimulate is the opioid-based soothing system, which plays a crucial role in stress response, emotional regulation and motivational processes (Carona and Marques, 2023). CWI has also been found to provide an anti-inflammatory response, which may attenuate inflammatory-based depressive disorders.
Research published earlier this year defined the neural mechanisms underpinning how cold water causes changes in the brain (see Figure 1), presenting the effect of CWI on brain functioning (Yankouskaya et al. 2023).
The current viewpoint on contemporary application to mental health disorders, published a matter of weeks ago suggests how psychobiological mechanisms of CWI might interplay with depression (see Figure 2).
The use of cold water swimming is thought to provide accompanying beneficial mechanisms such as health benefits derived from exercise and ‘green therapy’ and ‘blue therapy’, which suggests the psychological benefits of being in green natural landscapes or around bodies of water (Figure 3) (Tipton et al. 2017).
More research published earlier this year showed it was safe and feasible for people with depression to undertake regular CWI (Hjorth et al. 2023). Other research on CWI is of low methodological quality, with small case studies and anecdotal evidence (Massey et al. 2023). Following recurring recommendations across recent research, this study aims to assess the efficacy of CWI on people with mild-to-moderate depression.
Figure 1. This graphical abstract provides a visual representation of the bivalence of neural processes in response to CWI, whereby decreasing negative affects and increasing positive affects occur independently (Yankouskaya et al. 2023).
Figure 2. This graphic hypothesises the link between CWI and depression and anxiety symptom reduction (Carona and Marques, 2023).
Figure 3. This diagram shows how multiple factors of CWI may interplay in MDD, such as social aspects, mindset aspects and the impact of nature (Tipton et al. 2017).
References
Carona, C. and Marques, S. (2023) ‘Beyond the cold baths: contemporary applications of cold-water immersion in the treatment of clinical depression and anxiety’, BJPsych Advances, pp.1-3.
Hjorth, P., Sikjær, M.G., Løkke, A., Jørgensen, A.M., Jørgensen, N., Kaasgaard, D.M. and Rasmussen, M.R.V. (2023) ‘Cold water swimming as an add-on treatment for depression: a feasibility study’, Nordic Journal of Psychiatry, 77(7), pp.706-711.
Massey, H., Denton, H., Burlingham, A., Violato, M., Bibby-Jones, A.M., Cunningham, R., Ciccognani, S., Robertson, S. and Strauss, C. (2023) ‘OUTdoor Swimming as a nature-based Intervention for Depression (OUTSIDE): study protocol for a feasibility randomised control trial comparing an outdoor swimming intervention to usual care for adults experiencing mild to moderate symptoms of depression’, Pilot and Feasibility Studies, 9(1), pp.122.
Tipton, M.J., Collier, N., Massey, H., Corbett, J. and Harper, M. (2017) ‘Cold water immersion: kill or cure?’, Experimental physiology, 102(11), pp.1335-1355.
Yankouskaya, A., Williamson, R., Stacey, C., Totman, J.J. and Massey, H. (2023) ‘Short-term head-out whole-body cold-water immersion facilitates positive affect and increases interaction between large-scale brain networks’, Biology, 12(2), p.211.