HOT AND ICE BATHS: WHY TAKE THEM?
" If you want to be great, these are the kinds of things you have to do, even when you don't feel like it ." - Usain Bolt
Professional football players regularly tout the benefits of alternating hot and cold water for recovery between matches, particularly through the use of contrast baths .
This practice, known as hydrotherapy , raises a question: what are the benefits and what actually happens in the body when one is exposed to boiling or ice water?
WHY PRACTICE HYDROTHERAPY?
To understand why hot and cold baths are so popular with athletes, you first need to look at what happens in your body when it comes into contact with water, depending on its temperature.
Heat causes vasodilation . Your blood vessels dilate, which increases blood flow to your muscles, relaxes your muscles, and facilitates the release of tension in the tissues.
A hot bath also promotes mental relaxation, impacting your stress and sleep.
Cold causes vasoconstriction which, conversely, causes your blood vessels to constrict.
This has the effect of limit inflammation and the accumulation of metabolic waste in your muscles, quickly relieve your muscle pain and stimulate the release of endorphins.
Cold weather is also said to be beneficial for stress management and strengthening immunity .
Alternating hot and cold combines both effects: it stimulates circulation by creating a vascular pumping action that promotes the elimination of metabolic waste.
This thermal alternation would be particularly effective in accelerating recovery after intense exertion
Several studies demonstrate that regular exposure to these thermal stimuli improves recovery markers, reduces perceived pain, and promotes better adaptation of the body to stress.
BENEFITS OF COLD BATHING
You've probably already seen it on the social media of top athletes: those pools filled with ice cubes into which athletes plunge after their training.
Beyond the fad, this practice offers benefits for the body, both physical and mental.
How does it work?
Immersion in cold water causes vasoconstriction , that is, a contraction of the blood vessels which reduces blood flow to the muscles.
This has two key effects:
By limiting blood flow, cold reduces the arrival of inflammatory mediators and slows the accumulation of metabolic waste in muscle tissue.
Cold acts as a natural analgesic . It slows nerve conduction and reduces the sensation of pain as well as markers of muscle damage such as creatine kinase .
Namely
Studies have shown that 10 to 15 minutes in water between 10 and 15 °C after intense exercise significantly reduces the perception of muscle pain in the 24 to 48 hours that follow.
And that's not all.
Cold also activates the sympathetic nervous system, boosts the release of noradrenaline and endorphins, and leads to a slight rise in cortisol.
Put simply , you feel a boost of energy, increased alertness and sometimes a slight euphoria right after getting out of the bath.
The limits of the cold bath
Be careful not to overdo it. If you're doing sports to gain strength and muscle, systematically taking ice baths after each session can slow down your progress .
Why? Because cold limits inflammation, which is necessary for adaptation and the synthesis of muscle proteins.
Several studies have shown that post-workout cold immersion can reduce hypertrophy and long-term strength gains if used too often.
It is therefore better that you use it occasionally , in a targeted way, in a competitive setting or during a series of intense training sessions when you accumulate a lot of fatigue.
Summary
BENEFITS OF A HOT BATH
In contrast to cold baths, hot baths rely on gentleness and warmth to soothe the body .
Practiced for centuries in Asian cultures (onsen in Japan, hammams in the East), hot baths are renowned for their physical and mental benefits 👇
How does it work?
Immersion in hot water causes vasodilation , that is, a widening of the blood vessels.
This has several beneficial effects:
By dilating blood vessels, a hot bath increases blood flow, allowing for better transport of oxygen and nutrients to your muscles. This promotes tissue repair and reduces feelings of fatigue.
Heat acts on muscle fibers by reducing their tone , which helps to release tension. It is particularly beneficial in cases of stiffness, contractures, or persistent muscle knots.
By stimulating venous circulation, hot water facilitates the drainage of waste products produced by exertion (such as lactic acid ), which accelerates your recovery and reduces the feeling of muscle heaviness.
Hot water activates the parasympathetic nervous system, the one that induces a state of rest.
This therefore leads to a reduction in your stress, an improvement in your sleep, and a feeling of overall relaxation, impacting both your physical and mental recovery.
What science says
- A study has shown that immersion in 40°C water for 20 minutes improves muscle recovery and reduces perceived pain , without disrupting adaptive processes.
- More recent research even suggests that heat could better maintain muscle performance in the days following intense exercise, compared to cold water.
- A study has shown an increase in muscle mass and strength after regular exposure to heat, as well as a slowing of muscle breakdown during rest phases.
BENEFITS OF CONTRASTING BATHS
The best of both worlds?
You might be wondering whether a hot or cold bath is more suitable for your situation. The answer may be to practice both , through contrast bath therapy.
How does it work?
The alternation between heat (vasodilation) and cold (vasoconstriction) causes a vascular pumping effect, which promotes:
The pumping effect created by alternating hot and cold facilitates the elimination of waste products that accumulate after physical exertion. This helps reduce the feeling of heavy legs and general muscle fatigue.
Changes in temperature cause the diameter of blood vessels to oscillate (the "pump" effect), which stimulates circulation. Blood, rich in nutrients and oxygen, reaches the areas being repaired more efficiently.
By avoiding prolonged exposure to cold, you limit local inflammation without eliminating it completely . This helps relieve pain while allowing natural muscle regeneration processes to occur normally.
What science says
Several studies have shown that alternating hot and cold compresses after exercise significantly reduces muscle pain in the hours and days following intense training.
On average, people who use contrast baths report less muscle soreness 24, 48, or even 72 hours post-exercise, compared to those who do nothing.
The observed benefits are comparable to cold and hot baths alone. In short, it remains an effective solution for enjoying the benefits of both methods without their drawbacks.
PRACTICAL RECOMMENDATIONS
Extreme temperatures, whether cold or hot, can stress your body if you are not used to them.
So proceed gradually, especially during the first sessions, to avoid any excessive reaction.
Once you're used to it, here are the practice recommendations to best benefit from the effects on recovery:
Time : 10 to 20 minutes.
Temperature : between 38 and 45 °C.
Context : in the evening for better sleep, several hours/days after your session.
Other recommendations : practice as much as necessary, remember to drink water because the heat dehydrates you.
Time : 10 to 15 minutes.
Temperature : between 10 and 15 °C.
Context : right after a session, when you feel a lot of muscle fatigue, if you want to do a series of sessions/competitions.
Other recommendations : do not train constantly for muscle synthesis.
Time : alternate 2-3 minutes of hot bath and 30 seconds to 1 minute of cold bath.
Temperature : hot 38-45°C, cold 10-15°C
Context : at any time, whenever you are looking to recover.
Other recommendations : finish with something hot if you are looking to relax (in the evening), finish with something cold if you are looking for a boost (in the morning).
CONCLUSION
Whether it's to soothe your muscles after exercise, calm your nervous system, or boost your adaptability to stress, water is a valuable ally in your quest for performance and well-being.
Adapt this practice to your goal and be consistent . Optimizing your recovery is an investment in your progress. The more you understand and intelligently apply the right protocols, the faster you'll advance and achieve your goals.
FAQ
An immersion bath involves complete immersion of the body in water, which creates uniform pressure on the vessels and tissues, and alters the temperature not only of the skin but also of the muscles and joints deep down.
In a shower , water flows over the surface of the body without uniform pressure, which acts mainly on the skin and superficial level.
If your goal is muscle recovery, a full bath will be more effective. However, if you're looking for a gentler effect (waking up, nerve stimulation, mood improvement), a cold or hot shower may suffice, without requiring the time or setup of a bath. Showers can also serve as a gradual introduction to thermal exposure, especially if you're not used to it.
We can say yes .
Alternating hot and cold water capitalizes on the effects of the two extremes: vasodilation (hot water) then vasoconstriction (cold water).
This oscillation improves the drainage of metabolic waste, facilitates the delivery of oxygen and nutrients to the muscles, helps reduce inflammation and accelerates recovery.
Numerous studies and anecdotal evidence show that immersion in cold water after exercise can reduce the perception of muscle soreness in the following 24-48 hours. This is due to vasoconstriction (reduced blood flow and therefore local inflammation) and an analgesic effect from the cold.
Yes.
Systematic cold immersion after each session may diminish long-term strength/mass gains.
On the other hand, hot baths or contrast baths , practiced in moderation, seem to have no negative impact on muscle adaptation, with heat even potentially benefiting muscle synthesis according to some studies.
Yes.
Sudden exposure to very cold or very hot water can shock the body, causing dizziness, palpitations, and cardiovascular stress. It's important to proceed gradually, especially at first.
Furthermore, if you suffer from circulatory problems, cardiovascular problems, hypertension, or other chronic conditions, it is recommended to consult a healthcare professional before adopting hydrotherapy.
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