Every year the American College of Sports Medicine publish their annual review. This year the survey recorded the responses of 4,133 exercise professionals from around the world. The review includes a list of the top trends for 2018. Topping the bill this year was HIIT, or high intensity interval training. The training itself is designed burn calories quickly, with fast paced bursts of energy mixed with little to no rest. Some research has suggests 20-30 minute sessions can burn more calories and keep your metabolism high long after you finish your routine. So, is long, slow, endurance training useless and destined to be ditched? I really hope not!


The Benefits Of HIIT

This will be a brief overview and most likely covered in more detail in another blog! Despite using high power movements and short bursts, HIIT is more aerobic than you think. The short rests deny you the opportunity to recover quick enough to use your anaerobic energy systems. You’re using Oxygen and lots of it at that! This isn’t a bad thing and has many benefits for your “cardio”. Working at 90% of your VO2 Max has show the following adaptations:

  • Increased number, size and efficiency of Mitochondria (just think, the powerhouse that create energy within your muscles).
  • Increased oxidative enzyme activity (think better at turning fuel into energy).
  • Improved A-V O2 Difference (basically you use more oxygen and more efficiently).

These all happen within the muscles themselves. So you’re improving your cardio, without improving the heart and lungs? Whilst you will get some more central adaptions, you’re missing out, big time.


Key Adaptations to Endurance Training

Improving how your muscles create energy and utilise oxygen is great. But wouldn’t;t it be great if you could get MORE oxygen to them in the first place?! Working out at a much lower % of your VO2 Max for a sustained period has been shown to cause multiple central adaptations:

  • Increased cardiac output is the most significant adaptation to occur. This simply means you can pump more blood around your body each minute. There are a few reasons for this, including;
    • Improved stroke volume (more blood pumped each beat).
    • Cardiac hypertrophy (your heart literally gets bigger and stronger).
  • The Volume of your blood increases. Levels of Plasma and Haemoglobin increase, meaning you can carry more oxygen within the blood.
  • Increased capillarisation (the small vessels that carry blood from your arteries to your muscles).

The list is longer than this but these sum up the most important. Essentially, your become really good at taking in oxygen and really really good at siding it around your body.


A Personal Touch For Performance

At NK Fitness, we pride ourselves on creating the perfect sessions for you. The next time you book in for a session of Personal Training in Twickenham we’re going to build it around you. If you do a lot of high intensity work, you may be really good at getting the muscles to utilise oxygen. This would mean it’s likely we would focus on longer, steadier workouts to improve HOW MUCH oxygen you can deliver to the muscles. It’s a balancing act, make sure you’re not tipping the scales too far one way.