An important question when establishing your ice bath / cold therapy practice is to set a time each day that you commit to doing the plunge. While for some, time of day is a matter of preference (a lot of people like first thing in the morning for habit-forming purposes), there are some key considerations to keep in mind:
Morning: Best for mental alertness and energy during the day. Exposure to cold water or cold air can stimulate the body and mind, helping you feel more awake and ready to take on the day. Additionally, morning exposure to cold has been shown to improve sleep quality at night.
Afternoon/Evening: Best to reduce stress and promote relaxation. Exposure to cold can stimulate the production of endorphins, which are natural painkillers and mood boosters. Cold therapy may also help reduce inflammation, which can contribute to feelings of stress and anxiety.
Before/After Exercise: Best to reduce muscle soreness and speed up recovery time. Some athletes choose to take cold showers or ice baths after a workout to help their muscles recover and reduce inflammation. However, it is important to wait 6 hours after strength training to take an ice bath if you are trying to build muscle mass as it can interrupt hypertrophy.
In the end, the optimal time to do ice baths / cold therapy is the time that works best for you and your schedule. Whatever time is best for building a long term, consistent practice. It's important to start slowly and gradually increase the intensity and duration of your cold exposure, while listening to your body and adjusting as needed.