Cold Plunge And Sleep: Do Ice Baths Help Your Zzzs?
In the current wellness landscape, the therapeutic potential of ice baths is one of biggest topics of discussion, championed by influential figures such as Joe Rogan, Andrew Huberman, and Russell Brand.
Anecdotally, some people report having the best sleep following a habituated cold plunge ritual. The positive effects on the nervous system of any icy plunge could be the key to getting a better nights rest.
The sleep improvement journey, marked by experimentation with various strategies for enhancing sleep, like supplementation, meditation, breathing techniques and other sleep hygiene practices, should also make room for ice baths.
While the general reasons surrounding using ice baths for health typically centres on mental health benefits, weight management, and exercise recovery, a less heralded yet compelling reason emerges—the influence of cold therapy on the quality of sleep.
Why Ice Baths For Sleep?
Decreasing body temperature is associated with improved sleep because it is part of the natural circadian rhythm and sleep-wake cycle. Some studies indicate that cold water immersion positively impacts sleep architecture and recovery in athletes, which can be a game changer for athletic performance.
The body's core temperature naturally drops as part of the sleep initiation process, and this decrease in temperature plays a crucial role in promoting and maintaining restful sleep.
So what are the factors that may contribute to an ice bath being good for promoting sleep?
Circadian Rhythm:
The human body has an internal biological clock known as the circadian rhythm, which regulates various physiological processes over a 24-hour cycle, including the sleep-wake cycle.
The circadian rhythm is influenced by external factors such as light and darkness, helping to synchronize the body's functions with the day-night cycle.
Temperature Regulation:
Core body temperature is one of the physiological variables regulated by the circadian rhythm.
Body temperature typically follows a daily pattern, with the lowest point occurring during the early morning hours (around 4 a.m. to 6 a.m.) and the highest point in the late afternoon.
Thermoregulation and Sleep Onset:
Sleep onset, the transition from wakefulness to sleep, is facilitated by a drop in core body temperature.
As you approach bedtime, your body begins to lose heat, promoting relaxation and drowsiness.
Cooling of Extremities:
Peripheral body parts, such as hands and feet, also play a role in temperature regulation. Cooling these extremities helps signal to the body that it's time for sleep.
This is why some people find that keeping their hands and feet warm or cool can affect their ability to fall asleep.
Sleep Environment:
Creating a cool sleep environment can aid in the natural decrease in body temperature. A cooler room temperature is often recommended for optimal sleep.
Melatonin Release:
The decrease in body temperature is closely linked to the release of the sleep hormone melatonin, which helps regulate the sleep-wake cycle.
Temperature-Regulating Mechanisms:
During sleep, the body's thermoregulatory mechanisms continue to work to maintain a stable core temperature.
In the absence of external factors (like a warm room), the body can efficiently dissipate heat, contributing to a more comfortable and uninterrupted sleep.
Should I Ice Bath Before Bed?
In terms of timing your ice bath for the purpose of improving sleep, it is worth considering the ‘rebound effect’ that can occur after submerging the body in cold water.
The "rebound effect" from cold exposure refers to the body's response after being exposed to cold stress, and it can be an important consideration, especially when taking ice baths before bed. In the context of pre-bedtime ice baths, there are a few key processes that would indicate that it may be a good idea to have at least a few hours of separation between you ice bath and your actual bed time.
Cold Exposure and Thermoregulation:
When exposed to cold, the body initiates mechanisms to maintain its core temperature. This includes vasoconstriction, shivering, and other responses to conserve heat.
Rebound Increase in Metabolic Rate:
After exposure to cold, there is often a rebound increase in metabolic rate when returning to a warmer environment. The body expends additional energy to generate heat, helping to restore normal body temperature.
Post-Cold Vasodilation:
Following cold exposure, there can be a phase of vasodilation, where blood vessels expand. This promotes increased blood flow and contributes to the sensation of warmth as the body redistributes heat.
Hormonal Changes:
Cold exposure may lead to changes in hormone levels, such as an increase in norepinephrine. Norepinephrine is involved in the body's stress response and can influence factors like heart rate and blood pressure.
Brown Adipose Tissue Activation:
Cold exposure activates brown adipose tissue (BAT), which generates heat. This activation is part of the body's adaptive response to cold and contributes to the rebound effect.
In summary, the natural drop in body temperature is a key component of the body's preparation for sleep. So, while ice baths initially drop the body core temperature, the rebound effect would generally produce an increase in body temperature close to bed time, which is generally considered unfavourable for transition into the early stages of sleep.
Conclusion
Overall, there is evidence to suggest that ice baths are good for sleep, but timing is important to maximise the potential benefits.
With ice baths being well known for their ability to activate the parasympathetic nervous system and promote a state of rest and relaxation, there is a lot of merit in using ice baths to improve your sleep quality.
We recommend timing your ice bath about 1 to 2 hours prior to your bed time to allow for the body temperature to naturally rebalance and allow for the relaxation effect of cold immersion to take effect.
With many people opting for ice baths as a way to boost energy and focus, it could be far more beneficial to opt for your ice bath ritual closer to the morning to get the ‘best of both worlds’. It may also be highly useful to track your sleep using a sleep tracking device or a journal to see which time of day works best for you in regards to ice baths for sleep.
