Is shorter better?

Q) Are shorter HIIT workouts more effective than longer ones?

A) As we've suggested in previous blogs, you're likely to be interspersing your workouts with some high intensity interval training or HIIT. Aren't you?!!!!

Some recent research suggests that to get the full benefit of HIIT, less may be as beneficial or even more beneficial than doing more. (1) HOORAY!!!!

The research I'm referring to is an analysis of several studies using sprint interval training or SIT (...clever name!). This is a very intense training method and was done, in this instance, on special spin bikes. The author of the study does suggest that working as hard as you can is relative to everyone (they should have used MYZONE?). What it showed is that past a certain point, doing more was no longer beneficial and in fact started to become detrimental to improvements in VO2 - the measure of fitness being assessed in this case. 

So, the fact you have to do HIIT for less time to get better VO2 fitness results is the good news, right?! AND, if planned correctly, a shorter HIIT period in a workout could mean more time left over for skill development exercises like, training abs in tension or working glutes at end range for example. See previous blog.

Delving a little deeper into the whys and wherefores of HIIT. It is an exercise modality that has been and continues to be studied extensively. And because it's so popular, for good reason too.

Many people seem to find it more enjoyable than more continuous styles of exercise. (2). If you've ever heard "I don't like running, it's boring" you'll appreciate this. But, to buck the trend of time spent doing = value for money, we want to make sure people are walking away having felt they've worked hard. HIIT delivered well certainly does that. It's much easier to convince people (not necessarily athletes) to work hard for 20 seconds than it is getting them to work hard for 2 minutes on the same thing - probably the main reason why it's popular.

HIIT also has many health benefits (3,4,5,6). These range from helping with glucose control - important for assisting the prevention of type 2 diabetes to improving cardiovascular health and the rehabilitation of people with cardiac disease. The short time frame within HIIT needs to be done to gain benefits is most significant in and better suited to these groups of people. Good luck convincing them HARD = GOOD!

Generally speaking;

For those of you that are fitter and looking to get fitter still, the intervals used for HIIT can really be dependent on what you're training for. This is the science of specificity and is lost on most trainers unfortunately. A stop-start team sport player (football/soccer/badminton) may want to do a more Tabata style 20secs of extremely hard exercise with 10seconds rest OR 20/40 on/off. If you're looking to improve your 5k time you may want to look to increase your lactate threshold, so perhaps 60secs on with 30secs rest or 60/120 on/off would be good here. I still maintain rest is for whimps. But that's just me. Carry this on for 30-minutes and leave 15-minutes at the end for skill development.

Exercise choice is also important here, so be specific to goal, work variables to improve skill base and choose the correct timings for your workouts.

Specifically speaking;

Again and to follow on from that it's worth being very clear how specific the body is in its adaptation to exercise. Although both HIIT and continuous endurance exercise have an effect on VO2, they do have different effects in the preparation of muscles. So, if you're marathon training you need to run longer as the muscular adaptation is different from that felt during HIIT (7). We could go on about specificity, but let's not here.

 So there you are, for fitness - short sharp painful and full of benefits, just the way we like it.

 As always. Never made up on the spot.

 1) Effect of Number of Sprints in a SIT Session on Change in VO2max: A Meta-analysis.

Vollaard, Niels BJ; Metcalfe, Richard S; Williams, SeanMedicine & Science in Sports & Exercise:

Post Acceptance: January 10, 2

2) High-Intensity Interval Training Elicits Higher Enjoyment than Moderate Intensity Continuous Exercise.

Thum JS, Parsons G, Whittle T, Astorino TA.

PLoS One. 2017 Jan 11;12(1):e0166299. doi: 10.1371/journal.pone.0166299.

3) High-intensity interval training: a review of its impact on glucose control and cardiometabolic health.

Cassidy S, Thoma C, Houghton D, Trenell MI.

Diabetologia. 2017 Jan;60(1):7-23. Review.

4) High-Intensity Interval Training Versus Moderate-Intensity Continuous Training in the Prevention/Management of Cardiovascular Disease.

Hussain SR, Macaluso A, Pearson SJ.

Cardiol Rev. 2016 Nov/Dec;24(6):273-281. Review.

5) Comparison of Different Forms of Exercise Training in Patients With Cardiac Disease: Where Does High-Intensity Interval Training Fit?

Gayda M, Ribeiro PA, Juneau M, Nigam A.

Can J Cardiol. 2016 Apr;32(4):485-94. doi: 10.1016/j.cjca.2016.01.017. Review.

6)Modified high-intensity interval training reduces liver fat and improves cardiac function in non-alcoholic fatty liver disease: a randomized controlled trial.Hallsworth K, Thoma C, Hollingsworth KG, Cassidy S, Anstee QM, Day CP, Trenell MI.

Clin Sci (Lond). 2015 Dec;129(12):1097-105. doi: 10.1042/CS20150308.

7) Differential Motor Unit Changes after Endurance or High-Intensity Interval Training.

Martinez-Valdes E, Falla D, Negro F, Mayer F, Farina D.

Med Sci Sports Exerc. 2017 Jan 23. doi: 10.1249/MSS.00000000