It depends.
The number one priority is to ensure you are implementing cold exposure in a safe way. There are some risks with getting into cold water so it is important to take it slow and gradually increase the intensity.
We'll discuss 3 different methods for determining how long you should stay submersed in cold water: Intuition, Time, and Walls
Intuition
Our favorite way of determining how long you should stay in the plunge is by using your intuition and feeling into your body. Get into the plunge, calm your breathing and create stillness in your mind. Focus on slowing your breathing down, tune into your heart rate and slow it down. Stay here in the present moment and just feel into the sensation with no judgement. When you begin to shiver or feel the time is right, take your time slowly getting out. We have found that many people will easily do more than 2-3 minutes in 40°F water their first time using this method. As you become more cold tolerant, naturally your time will increase.
Time
Using time is probably the most popular way that the cold-blooded community measures their submersions in the ice. While this is a great method for building discipline and having a quantitative tool to measure, we have found that too much of a focus on time will not allow the plunger to fully drop into the experience and can actually decrease the amount of time they can embrace the cold. When using time as your tool to determine how long to stay in the plunge, we recommend setting a timer and doing your best to not continuously check it, just drop in and allow it to go off when you reach your goal.
So how long should you stay in the plunge? If you're new to cold water exposure, we recommend starting with as little as 30 seconds and working your way up as your tolerance increases. According to Dr. Andrew Huberman, a solid science-supported protocol for cold exposure is 11 minutes TOTAL per week over 2-4 sessions with a duration of 1-5 minutes each. Our philosophy is that you can get ~90% of the physical benefits in a 2 minute plunge, anything over 2 minutes becomes a challenge of the mind.
Walls
A protocol coined by the Huberman Lab, the Wall method is the idea that during an ice bath, we are faced with the challenge to get out or continue to push ourselves a.k.a. a wall to traverse. Setting a goal of traversing 3-5 walls is a good way to quantify the time in the ice. By getting into the ice bath, our body engages in a primal response by releasing adrenaline and noradrenaline, signaling the "fight or flight" response; by breathing and overcoming this "wall" we create discipline and increase our willpower. Throughout consistent practice with cold plunges, you may find the duration between each "wall" increases and the effort to overcome each one decreases. This is a great method that is transferable to life's stressors as "walls" will not always be easily defined by a time metric.
Conclusion
The best way to determine what method works for you is to practice and experiment, keeping your cold plunge routine fun and engaging. Remember, the cold is not a punishment but an act of self care and commitment to growth.
Resources:
Huberman Podcast:
Disclaimer: For informational purposes only, always consult with a professional and prioritize safety when beginning a cold exposure routine.