In this video I’ll be talking about heat shock; cold shock; and also a little about HIIT exercise.

One thing I’ve learned in the past few years is that comfort kills.  The more pampered and comfortable we are, the more the aging process tends to creep up on us.

  • We live in homes that are kept warm and toasty. This feels great, but stops our bodies and mitochondria from the challenge of adjusting to temperature changes. (There’s no need to adjust our temperature internally if we can do it with a thermostat. So our mitochondria get lazy. Why work if you don’t have to?)
  • We have constant access to food. This does keep us well-nourished, but it also raises our glucose and insulin levels, and stops our bodies from producing human growth hormone, if we’re nibbling constantly.
  • We (or most of us) drive or call and Uber or take a bus to get to other places instead of walking or running. So we lose muscle tone and strength as the years go by. 
  • The more comfortable we are, the faster our bodies decline. So I’ve learned, and am still learning, to challenge myself physically in small ways every day.

Step 1: I start most mornings with a CONTRAST SHOWER:

  • 3 minutes of hot
  • 1 minute of icy cold
  • 3 minutes of hot
  • 5 minutes of icy cold

By the end of the shower, I’ll have had six minutes of hot and six of cold.

Even after doing contrast showers over a year, I don’t look forward to them. I hate the first round of cold. But I’m usually fine by the second round. I find the cold difficult if I’m paying attention to it. I do thinks like belting out songs or doing multiplication tables during the last 5 minutes. (I know some people might doing multiplication tables more irksome than the cold showers themselves.)

It’s important in a contrast shower to make the hot water as hot as you can stand (without scalding yourself) and the cold water as cold as you can stand. And always end on cold, because this forces your mitochondria into biogenesis. The point is to make the little guys work for a living, not to make it easy on them.

  • Both cold shock and heat shock show evidence of triggering a response in your mitochondria, raising NAD levels and triggering mitochondrial biogenesis.
  • Oh, and, the cold hitting your white fat will turn it into brown fat, which burns body fat to produce heat.  (White fat is inert, and dangerous; brown fat can be beneficial.)
  • It turns brown because it’s filling up with new mitochondria. This literally makes the fat in your body change color, and function differently.
  • As a side benefit, I haven’t gotten more than a trace of a cold since starting this regimen. The times one started up, it was gone after the shower.
  • ONE CAUTION: If you work out and are trying to increase your muscle mass, it is not recommended to have cold showers right after your workout. There’s growing evidence that they dampen the hormetic response to exercise that increases muscle size. It appears wisest to space cold showers at least two hours before or after a workout.

Someday I’ll shock the world with a video of me showering, Ben Greenfield-style. (“Look at me! I’m naked! Here I am stepping into the shower!”)

  • As a side note –– I like Ben.
  • And — he’s an athlete, totally ripped. I’m an old dude. So I’ll leave those kinds of videos to him.

How I started out

I started doing contrast showers in September 2018. I’ve done ’em every day since then (except for one, when I was racing the clock and had tn time). When I started, I could only stand a few seconds of cold. It got easier, as my white fat turned into brown fat and my body adapted to the challenge. I built up gradually to where I can do several minutes of cold water at a time.

Shower’s over? Try some red light therapy

  • Shower’s done. Time to “feed my mitochondria” with some red light exposure.
  • I go stand between two rows or red lights, 660 nm on the left, and 630 nm bulbs on the right, about a foot away from my skin… do both sides… then repeat the red light exposure with the lights a few inches from my skin. Sometimes I press them right up against parts of my body and hold them there for a minute or so.
  • I put on some music or a podcast and get lit for a while.
  • These lights are not lasers, they are LEDs, and are cool to the touch. I don’t know if the effect is physiological or psychological… probably a little of both.. but it definitely revs me up for the day.
  • Too Much Information Department: At the end of a session, I’ll press both types of lights directly against my testicles to stimulate the production of testosterone. It gives me a jolt of sexual energy when I use the lights that close to the skin.


  • I’d love to get sun exposure every day. But I live in a part of the world which is overcast much of the time. (The sun’s out, but it’s filtered through a heavy layer of clouds. But I do get it when possible.
  • When I am able to get sun exposure, since starting to take astaxanthin, I no longer burn, so I don’t use any sunscreen. (I prefer not to use it because of the toxins in it.) (I am not making any recommendations about whether other people should use it or not; what you do in your life is up to you.)
  • For those who do want to use sunscreens, there are some that are less toxic, both to the people using them and to the environment. 


  • Short bouts of vigorous exercise, pushing myself till I’m out of breath to create an oxygen deficit, as a way of cranking up my body’s production of NAD+.
  • I like driving down to campus early (before teaching), and running some outdoor stairs.


Two things are on my agenda for this coming year:

  • Installing a home sauna. (Does anyone have any advice on which one to to buy?
  • Setting up a home gym. (Same question. I would really, really like to set up a climbing area of some sort in my basement or back yard.)