Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...Tell Me More
For today’s edition of Dear Mark, I’m answer two questions from readers. First, does Bikram yoga qualify as sprinting or high intensity training? It’s certainly intense, and it’ll make you sweat bullets and work hard to the point of nausea, but does it actually accomplish the same training effects as sprinting or intervals? Find out down below. Next, you often hear that body fat is the main repository for environmental toxins. This is true, but does that mean the body “holds on” to body fat to prevent systemic dispersal of the toxins it contains? Can stored toxins make losing body fat harder that it already is?
I love doing Bikram yoga and wonder if you would consider it a sprint day or a high intensity day, or both?
Neither, actually. What do sprinting and other types of high-intensity training do to the body?
They preferentially burn body fat. Bikram yoga has been shown to induce modest reductions in the body weight of obese subjects, but that’s about it. There’s no indication that Bikram has significant or unique effects on actual body fat.
They improve your ability to burn body fat throughout the rest of the day—the after burner effect.
They improve bone mineral density. Bikram may help younger women retain bone density (PDF), but isn’t enough to stave off the loss of bone density in older women (PDF). For that, you need impact and high stress—sprints and weights.
They increase mitochondrial biogenesis. This is the literal construction of new mitochondria, the power plants of the cell. There’s no evidence that Bikram yoga can induce mitochondrial biogenesis. You need intensity for that.
They take just a few minutes. This isn’t by design; when you’re sprinting or working at truly high intensities, you cannot do more than a few minutes of work. The effort required precludes high volume. Meanwhile, the average Bikram yoga session lasts about 90 minutes. There’s no way you can sprint for 90 minutes, or maintain high intensities for an hour and a half. It just isn’t possible.
They consist of moving really, really fast for short bursts. Bikram is movement but slow and gradual with lots of holds. If it can be classified as anything, it’d be isometric strength and flexibility training. Great stuff. Just not sprinting.
Of course, this isn’t to suggest that Bikram is pointless. It’s not. It’s great. There’s considerable evidence in favor of doing it, especially if you enjoy it.
One study found that 24 sessions of Bikram yoga in eight weeks increased deadlift strength, shoulder flexibility, and hamstring flexibility while modestly lowering body fat in healthy adults. The no-yoga control group had no such improvements.
Bikram yoga has also proven useful in the development of balance. Specifically, three sessions per week (identical to your schedule once again) seemed to help the most unsteady subjects improve their balance. Those subjects who were already pretty stable in unstable situations didn’t see as much of a benefit. Balance is crucial, not just for athletes but for older people who don’t want to fall and break any bones.
In another study, Bikram yoga reduced the time it took subjects to fall back asleep after awakening in the night. Subjects were quicker to fall back asleep on yoga days than on non-yoga days. Better sleep is incredibly important.
Bikram yoga is awesome stuff, but I don’t think it qualifies as sprinting or high intensity. That’s okay, though. It just means you can do Bikram and sprint (or do some alternatives) and get the benefits of both.
Thank you so much for the wealth of information and sage advice you provide on Mark’s Daily Apple! I love hearing your voice of reason on so many topics. I wasn’t able to find anything specific to this question on your website.
There is a lot of talk out there about “diets failing” because toxins remain trapped inside our bodies. Body fat is a form of protection, the body “enrobes” the toxins with fat to prevent organ damage. So until you find a way to eliminate them from your system, you won’t see long-term success with a dieting program. They also claim that when body fat is burned, the toxins become more concentrated in your body, causing the body to “rebound” and produce more fat to again store thhise toxins.
Now, many of those touting this viewpoint are selling “cleanse” products or products that “support the body’s natural functioning”. I am just wondering if there is any scientific research to support this claim that the body resists burning fat because it is being used to encapsulate toxins. I would love to hear your take on this.
Thank you so much!
They aren’t totally making things up. Adipose tissue does store toxins. A number of studies even indicate a relationship between recent weight loss and elevated serum levels of certain “toxins,” like persistent organic pollutants (which include certain pesticides, industrial chemicals, and pharmaceuticals).
In one, middle-aged people with a history of long-term weight loss had elevated levels of persistent organic pollutants. Those who hadn’t lost weight had lower levels. A more recent paper suggests this effect may be short-lived. Obese women who lost a ton of weight had elevated levels of POPs for the first 3 months, but at the 5-year followup, those who’d kept the weight off had lower levels of pollutants.
Visceral fat seems to store a greater proportion of pollutants. A recent study found that people who’d lost most of their weight in the belly had greater levels of pollutants than folks who’d lost mostly subcutaneous fat. Another measured pollutants in existing adipose tissue, finding that visceral fat contained more than subcutaneous. If the hypothesis is true, and body fat carrying the most pollutants is the most stubborn and hardest to lose, we’d expect that visceral fat is the hardest type to get rid of. But that isn’t the case at all. Studies show that visceral adipose tissue goes quicker than other types of body fat, even though it’s the highest in pollutants and other toxins.
Plus, it’s not like those toxins are totally innocuous sitting in body fat. They’re still in your body, and the evidence shows that higher levels of pollutants in adipose tissue correlate to more metabolic syndrome, especially poor blood sugar control and high blood pressure.
Everything equal, it’s better to lose body fat than hold on to it. Don’t let the fear of toxins keep you from losing excess body fat.
I haven’t seen any evidence that the body “knows” it’s storing toxins in fat and prevents weight loss to avoid their dispersal into circulation, though. If that’s the case, and the body is “smart,” it goes both ways: if you eat a weight loss diet replete in liver-supportive nutrients and maintain a healthy lifestyle, the body should “know” it can burn fat without overloading itself with toxins. I’m talking about:
Various phytonutrients from colorful fruits and veggies, spices like ginger and curcumin and garlic.
Plenty of exercise and sleep.
A month-long fast consisting of lemon, water, cayenne pepper, and activated maple syrup.
I’m kidding about one of those (it shouldn’t be hard to guess which).
But seriously: don’t worry about fat loss released toxins, or toxins inhibiting fat loss. I mean, what’s your other option? Accumulating even more body fat to act as reservoir for dangerous pollutants? It’s silly. Fat loss is consistently and almost unanimously linked to a bevy of health benefits. That research is conclusive. It’s vindicated. If you’re reading this and following a Primal Blueprint lifestyle, you’ve probably shed some body fat. Has it helped you or hurt you? Has it improved your quality of life or hampered it?
Thanks for reading, all. Take care. Be well.