September 15, 2025|כ"ב אלול ה' אלפים תשפ"ה Taking the Plunge: Ice Baths, Neuroplasticity, and Rosh Hashana
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About one year ago, I got an ice bath and I am proud to say I hardly miss a day of spending three minutes immersed in 45-degree water. Many studies now show the health benefits of cold exposure, from cardiovascular to controlling inflammation, from muscle recovery to increasing metabolism. When you get into an ice bath your body goes into a fight or flight, knows it can’t stay there forever, and the cold exposure causes a significant release of epinephrine or adrenaline and dopamine in the brain and body. These neurochemicals make us feel alert, awake, and energized. Each day after my “plunge,” I feel like I drank three cups of coffee and can lift a trunk. All of that is nice, but it isn’t what inspired me to buy it or why I use it.
Science used to believe that our brains were hard-wired, rigid, fixed, finite. But more recently, neuroscience has discovered that the brain is “plastic,” which means that it can change, it can be molded, and we can rewire. We aren’t born with specific personalities, feelings, thoughts, capabilities, skills, strength, focus, and that is it, we are fixed and stuck that way. Rather, we are blessed with the gift of neuroplasticity.
Neuroplasticity describes the brain’s ability to change throughout our lives. According to Dr. Norman Doidge, a neuroscientist at Columbia University, in his book, The Brain that Changes Itself, the brain plasticity exists from the cradle to the grave. New neural pathways can open, we can rewire our brain based on our habits, our behaviors, our choices, our efforts. Scientifically, a 100-year-old person, like any 10-year-old or 1-year-old, can still mold their brain, it is never too late. We can literally be reborn, we can recreate and rewire if we want to, if we choose to.
Rosh Hashana corresponds not with the first day of creation but with the sixth day, not with when heaven and earth came to be, but when we, humanity, were introduced to the world. This is because only then did the world have meaning and purpose and could be considered complete. On Rosh Hashana, we don’t say היום היה הרת עולם, today was the creation of the world. It isn’t just a birthday or an anniversary, we aren’t commemorating a historical event or something that happened in the past. Indeed, we aren’t even being judged for what we have done with our time since our creation until now; judgement is not for our past.
We say, הַיּוֹם הֲרַת עוֹלָם – today, YOUR new world is BEING conceived…and therefore, הַיּוֹם יַעֲמִיד בַּמִּשְׁפָּט, TODAY, you and I, we will be judged for what we do with the opportunity to be born again, to restart, to reset and to reboot. We cannot change the past, we cannot go back in time and make different choices. Of course we must take responsibility for the past, feel remorse and regret for it. But its real significance is what we learn from it, how we make changes to not repeat it, how we create a new future with our fresh start.
Chazal say (Rosh Hashana 16b) אין דנין את האדם אלא לפי מעשיו של אותה שעה, we aren’t judged for the past, we cannot change it. We are only responsible for the present, who we are right now, at this moment. We are evaluated based on what we do not with our birthday, the anniversary of our birth, but our “birth-day,” the day we are reborn, we get to start again.
Rosh Hashana as a gift of new beginnings, fresh starts, and clean slates is not only a metaphysical truth, it is evident in the physical world, too. We are evaluated not for what we have done since creation, but if we are choosing to embrace creation, the power to create again and again, to remold, rewire, to shape our brains and ourselves.
Rosh Hashana we are asked: Are you fixed or are you growing? Are you a finished product or a work in progress? Are you stuck in the past or improving for the future? Are you neuro-stuck or neuro-plastic?
Every single time I get into the ice bath I don’t want to. But I do it anyway and when I do, I am rewiring and changing my brain, not metaphorically or symbolically, but literally. There is a part of our brain in the cortex that controls willpower called the Anterior Mid-Cingulate, the AMC, and it turns out, when we perform an action or task even when we don’t want to, the AMC actually grows in size, it gets bigger and stronger and becomes more capable of completing tasks and actions out of our comfort zone. The challenge is that it only works one day at a time and needs to be renewed daily. If you return to your comfort zone, if you don’t push your limit, the AMC shrinks and goes back to its original size.
We live in an age of life hacks, shortcuts to accomplish things. But here is the thing: there may be hacks in technology and home improvement, but not in life. The only hack in life is to do the hard thing and when you do the hard thing, you become more capable of doing more hard things. We can sit in 45-degree water for three minutes. We can rewire ourselves to be selfless instead of selfish, to be calm instead of angry, to be patient instead of rushed, to be a giver instead of a taker, to live the life we have dreamt of living.
There is someone from another community who is looked up to for his generosity, volunteering, but also his religious commitment and practice. He doesn’t miss minyan, learns daily and inspires others. But it wasn’t always that way. In 2014, on Erev Yom Kippur, he wrote to his children:
My Dear Children,
Yesterday was an important day for me. For the first time in 25 years, I started to wear Tzitzis again. That is my commitment for the New Year. I just wanted you to know that the three of you were my inspiration to do it. Each of you in your own way and at different times made me think about how I can improve myself.
He then went on to spell out how each of his children’s growth motivates him.
He concluded: “So, in summary you three are my inspiration. Mom and I love you more than anything and wish you all an easy fast and the most unbelievable year. We are so proud of you. Words cannot describe.”
This grown man who hadn’t put on tzitzis in 25 years but he took the plunge and with it he rewired his brain. He grew his AMC stronger to add more and more to his life.
This Rosh Hashana should be a neuroplasticity day. Take some time to reflect and decide how will you rewire, what will you reprogram, which challenge will you take on, which comfort zone will you breach, will you take a plunge, will you have a change of mind and allow your mind to change.