In recent years, High Intensity Interval Training (aka HIIT) has become quite popular. If you aren’t familiar with the concept, HIIT involves alternating brief rounds of very intense cardiovascular exercise with lighter activity. For example, instead of going for a light jog for 30 minutes, a person engaging in HIIT might sprint as hard as they can for one minute, then walk for one minute, and repeat the process five times for a total ten minute workout.
There are many, many, different HIIT protocols, with perhaps the most famously brief one being a “Tabata”, in which a person does intense exercise (say pedalling as fast as possible on a stationary bike) for 20 seconds, pauses for 10 seconds to catch their breath, and then repeats the process eight times for a total four minute workout.
The advantages of this type of exercise are obvious to the time-crunched person, and I indeed frequently recommend doing a “Tabata” a few times per week to the patient who tells me they have no time for exercise. There is also a psychological appeal to HIIT training for the person who doesn’t feel like they are getting a good workout unless they leave the gym soaked in sweat. Crossfit for example has long incorporated a lot of HIIT work into their programs, and if you know any Crossfitters you will be aware these are not the type of people who are content to just go for a light walk or a gentle yoga class. (That’s not a knock on CrossFit nor the people who enjoy doing it by the way – the world contains many different personality types, and it’s great to have different fitness modalities that cater to these differences. It has simply been my experience that CrossFit tends to attract the “type A” personalities of the fitness world, people who really enjoy a workout that pushes them to the absolute brink of what they are physically capable of on a regular basis).
One of the things I frequently do on this blog is to critique medical studies. There are also now a lot of blogs, youtube channels, etc. that do the same. However, the average person (understandably) really has no training on how to read or critique a medical study, so it occurred to me recently that providing an occasional post explaining some of the concepts that are frequently used when discussing medical studies might be a useful service to my readers.
Accordingly, today I will explain “power”, which is the term used to describe whether a study is or is not robust enough to detect the effect of an intervention. Let’s start with a silly example.
In last week’s post, I outlined what NAD+ is; how it declines with age and the role that plays in aging; how it can be boosted with healthier lifestyle habits; how it can also be boosted with IV infusions or by taking the oral supplements NMN or NR; and why these supplements have generated tremendous interest in recent years.
But I also explained that, at this point in time, I do not recommend supplementing with NAD+, NMN, or NR. (Needless to say, I do recommend exercise and a healthy diet, both of which have been shown to raise NAD+ levels).
Pictured: Sir Arthur Harden, Nobel Laureate and discoverer of NAD+
I have not yet spent a lot of time on this blog discussing supplements, because I think the focus of good health should be the basics: healthy diet, exercise, good sleep, stress management, and the avoidance of toxic substances such as drugs, tobacco, and excessive alcohol.
This is not to say that supplements don’t have a role, but as a category they suffer from a number of problems. They often are not backed by large and robust studies. The studies that do exist tend to be funded by companies who stand to profit from the supplement, thus introducing the same conflict of interest that “big pharma” is often guilty of with prescription medications. They are not well regulated, so even if “substance X” is truly safe and terrific for your health, you have little guarantee when you purchase “substance X” that you are actually getting “substance X”, unless you make sure to purchase from a reputable place like FullScripts (linked here in case you are interested). And supplements can give people a false sense of security – “I take a multivitamin, and therefore I don’t need to worry about eating healthfully,” or “I take creatine, so I don’t need to actually do a workout” are foolish and potentially dangerous ideas.
With that said, I get asked about this topic a LOT, so I’m going to start periodically reviewing various supplements.
First up in today’s post: NAD+ (and the supplements which help to raise NAD+, namely NMN and NR), which a number of patients have asked me about in the past few months. This is a long and complicated topic and I had to do a lot of research to get up to speed on it, so I am going to break this post into two separate parts, one today and one a week from now. But first let me just give the punchline for those of you who don’t want to read my long ramblings:
I’ve discussed in a few prior posts (for example here and here) the potential downsides of doing too much testing in medicine. This is an important topic, and one that can be difficult to discuss. Patients – quite reasonably – want to feel that their doctors are listening to them, and running all reasonable medical tests to prevent, diagnose, and treat disease. Any discussion of how medical testing can sometimes actually be detrimental to your health can therefore risk coming off as being callous and uncaring. “What do you mean I shouldn’t be tested for disease x?,” a patient may think. “Don’t you want me to know if I have it or not?” Unfortunately it’s not so simple.
