In some corners of the internet there has been a bit of a backlash recently, with people like Mark Twight and Rob Shaul noting that while intervals can do a lot to benefit aerobic capacity, if you want to go long, sometimes you will need to train long too. ( I point to some of the discussion here). There was even a study recently that I saw some people jump on to say that intervals were nothing special or at least that they had been over hyped.
Effect of High Intensity Interval Exercise on Lipid Oxidation during post exercise recovery
The scientists compared intervals with a steady state session with respect to the effect on the amount of fat burned after the exercise was concluded. There was no difference.
Be that as it may this new research caught my eye.
Short bursts of intense exercise every few days could dramatically cut the risk of Type 2 diabetes and heart disease, according to an expert.
Rather than slaving away for hours in the gym, people should focus their attention on quick "sprints" with each workout lasting just a few minutes.
James Timmons, Heriot-Watt University professor of exercise biology has studied the effects of quick exercise.
He recommends 4 x 30 second sprints on an exercise bike three times a week.
He said people could reduce their risk of diabetes and heart disease substantially with short, intense workouts - with such "time-efficient" exercising appealing to busy workers.
The research that is referred to is here and the full paper is avaiable too.
Extremely short duration high intensity training substantially improves insulin action in young sedentary males
Classic, long duration aerobic exercise reduces cardiovascular and metabolic disease risk but this involves a substantial time commitment. Extremely low volume high-intensity interval training (HIT) has recently been shown to cause similar improvements to aerobic performance, but it has not been established whether HIT has the capacity to improve glycemic control.
Sixteen young men (age: 21+/-2 y; BMI: 23.7+/-3.1 kg * m-2; VO2peak: 48+/-9 ml * kg-1 * min-1) performed 2 weeks of supervised HIT comprising of a total of 15 min of exercise (6 sessions; 4-6 x 30-s cycle sprints per session). Aerobic performance (250-kJ self-paced cycling time trial), and glucose, insulin and NEFA responses to a 75-g oral glucose load (oral glucose tolerance test; OGTT) were determined before and after training.
Following 2 weeks of HIT, the area under the plasma glucose, insulin and NEFA concentration-time curves were all reduced (12%, 37%, 26% respectively, all P<0.001). p="0.058)." style="font-weight: bold;">Conclusions
The efficacy of a high intensity exercise protocol, involving only ~250 kcal work each week, to substantially improve insulin action in young sedentary subjects is remarkable. We feel this novel time-efficient training paradigm can be used as a strategy to reduce metabolic risk factors in young and middle aged sedentary populations who otherwise would not adhere to a classic high volume, time consuming exercise regimes.
I think the conclusion there is a really important thing. Intervals have a profound effect metabolically, they can have a major effect on health but they do not take long: 4 x 30 secs with some rests between sees the session over in 7 minutes a week. It is hard to claim that you do not have the time to do this. Some people are put off exercise because of the perceived time commitment but they need to know that they can exercise in such a way that they can benefit their health without needing much time.
Maybe other training protocols can have a similar impact....but none are as time efficient. I'd also argue that intervals are more natural and playful, but that is a different discussion.
The researcher here explained how intense intervals can help:
"Think about diabetes as being glucose circulating in the blood rather than stored in the muscles where it should be.
"If we take out the glycogen from the muscles through exercise, then the muscles draw in that excess glucose from the blood."
"If you go for a jog or a run you oxidise glycogen but you are not depleting the glycogen in your muscles.
"The only way to get to this glycogen is through very intense contractions of the muscles.
"If we can get people in their 20s, 30s and 40s doing these exercises twice a week then it could have a very dramatic effect on the future prevalence of diabetes."
Maybe the tide is turning and rational exercise (and diet) will oen day be mainstream? The video is worth watching.
As usual the NHS is sceptical!