Cognition & cold exposure

Updated: May 6

Your ice bath is probably good for your brain

Squinting Thomas P Seager, PhD with Pacific Ocean in background.
Caring for my brain is essential for my career as a scientist. This is me, at the beach in Monterey CA on one of my research trips working for the US Navy on infrastructure systems, getting my deliberate cold exposure between research workshops and presentations.

In 'Dangers of Deliberate Cold Exposure' I wrote:

The most dangerous thing about my 14 minute ice bath was probably the 20 minute drive I made afterwards.

My afterdrop was so bad that I shook for 10 minutes. I had no fine motor control, and I had to wait until I could operate my stick shift before I could speed off to my hot yoga class to rewarm.

Little did I know that my body was probably recovering faster than my brain.

Is my ice bath making me stupid?

Although research has shown that ten sessions of whole-body cryotherapy can improve memory in cognitively impaired individuals (Ramaszweska et al. 2018), a new article concludes that short-term cold exposure results in immediate loss of cognitive function (Falla 2021). Having reviewed 18 separate experimental studies, the authors wrote "Cold exposure induced an impairment of cognitive performance even before accidental hypothermia was established."

These findings sound alarming.

Brain health is not the kind of photogenic quality that attracts Instagram followers in our media-saturated culture, but it's one of the most important aspects of my career, my self-esteem, and my identity.

I spent over six years in graduate school to earn a doctorate in engineering. It took me ten more years to earn tenure. I moved my family and my young children through four different cities, chasing research grants, building laboratories, mentoring graduate students, and climbing in academic prestige. My whole life has been like one enormous smartness contest.

When Patrick Porter, PhD (right) measured my biological age with his BrainTap technology, and told me I was 30 years old -- two years younger than when he measured me a year ago -- I was both proud and relieved.

My Mother is not so fortunate.

The brain can age faster than the body

My Mother's brain is already gone. She suffers from Alzheimer's.

Back in 2018, before I knew anything about the metabolic origins of Alzheimer's (e.g., Kellar & Craft 2020) Mom was in a bad way. She was refusing her medications, physically abusing her nurses, and resisting her own care.

Her doctors told us that her behavior had become unmanageable.

I told them to discontinue all of her medications.

"To hell with her cholesterol," I said.
"I will not have my Mother lose a power struggle over the little remaining agency she has over her own bodily integrity.
"It is not dignified."

What if Mom was wrong?

Mom's health, mood, and behavior improved right away, and that experience become part of my own health awakening.

As I child, I thought my parents were the smartest people in the world. I know that's a natural position for any child to take, but my impression survived the usual rebelliousness, cynicism and disillusionment that comes with adolescence, because they had a lot of evidence on their side.

My parents met in graduate school at Harvard. My Father was a Professor of Education at the University of Pittsburgh, and my school teachers, principals, and administrators were all his former students -- or at least it seemed that way to me. He wasn't just the smartest man in my child world. The admiration and respect my teachers held for my Father meant that he seemed like the smartest man in their world, too.

He also had complex diet requirements that resulted from his extensive food allergies. So when my Mother read Diet for a Small Planet (Lappé 1971) and changed our meals towards more plant-based, more industrialized (e.g., margarine instead of butter), less fat, and more carbohydrates, I didn't see that as the act of political ideology that it was.

I thought it was because my parents were smarter.

As it turned out, the corn oil margarine, the skim milk, the breakfast cereals, the corn syrup concentrates... they were all contributing to my childhood obesity and her cognitive decline.

I don't want what she's going thru now to happen to me.

The ice bath is a workout for your brain

Whole body cold water immersion causes your body to produce a flood of neurotransmitters that alter brain functions. For example, plasma concentrations of norepinephrine and dopamine were increased by 530% and 250% respectively in young men immersed in 14C water (Šrámek et al. 2000). Because these chemicals act directly on our brains, they regulate biological impulses and emotions that drive changes in our mood, behavior, and thinking (Butnariua 2019).

One illustration of this effect is called ice face, and my daughter Emma exemplifies the phenomenon in the video below. It takes about 30 seconds for the norepinephrine synthesized near the kidneys to each the brain. At that point, after the gasp reflex has subsided and the pain of vasoconstriction is escalating, norepinephrine takes over the brain.

In Emma's case, the 30 second mark corresponds to the moment when she breaks into a smile and begins singing along with her music. At this point, there is little her brain can do but experience the biochemical changes taking place.

It wouldn't be a good idea to test her memory, her mathematical problem-solving skills, or her ability to maintain focused attention on cognitive tasks.

In short, her brain is busy.

It's no wonder that testing immediately after cold exposure reveals impaired cognitive performance.

Consider an analogy with exercising our muscles. When we work out, we fatigue our muscles and induce production of anabolic hormones like testosterone that stimulate recovery and growth of muscle tissues. During this period immediately after our workout, our muscles perform poorly -- not because we have made them weaker, but because they are busy becoming stronger.

Just like our muscles do not perform well when recovering, neither can our brains be expected to perform well when operating under the biochemical hormone rush of cold exposure. The immediate loss of cognitive performance experienced during rewarming after an ice bath is not an indication of some permanent injury -- it is consistent with a hormetic dose-response to heal