There are two types of intervals in my exercise life. Interval running sessions and high intensity interval training (HIIT). In this post I am going to try and explain why interval training is beneficial for heart, bone and muscle health. First an explanation of what interval training actually means. Basically it is a short period of very hard work – either running or doing some other exercise like skipping, jump squats or burpees – followed by a very short period of recovery. Repeat! And repeat again! And again! Typically interval sessions are not long, and sometimes very short. I have found that even 10 minutes of HIIT has a positive impact.
The aim of HIIT is getting muscles to work anaerobically rather than aerobically. Aerobic exercise is where oxygen initiates the production of energy in the cells of the body (aerobic cellular respiration) – the more energy required the more breaths you take, your heart beats faster to pump oxygenated blood around to all the muscles that are working extra hard, and you feel hotter as energy is converted from chemical to mechanical. The waste products of aerobic exercise are water and carbon dioxide – which are easily eliminated. There are many benefits of aerobic exercise including strengthening the heart muscle, improving lung capacity, reducing risk of Type 2 diabetes and metabolic syndrome, improving mood, and reducing cholesterol. Weight bearing exercise also strengthens bones. Aerobic exercise is any activity that raises your heart rate and increases breathing rate – walking a little faster is a great start!
Anaerobic exercise is the next stage. When the energy requirement is way more than than the body can deliver aerobically – for example when sprinting – glucose is converted to energy without oxygen in a process that is far too complicated to explain in this post (;-) ) but you can look it up here! The main waste product of anaerobic cellular respiration is lactic acid, and a build up of lactic acid in muscles can result in painful muscles and even cramps. During recovery periods you breathe in loads of oxygen and the lactic acid is oxidised and excreted as water and carbon dioxide. Anaerobic energy production is less efficient than aerobic which is why you can’t do it for so long. Aerobic respiration is 19 times more efficient than anaerobic! However practising high intensity intervals regularly helps muscles build up resistance to lactic acid, allowing faster and/or harder work for longer.
That’s why HIIT or doing fast intervals in running is good for increasing speed and reducing fatigue.
So what does a running interval session look like? There are many variations. This is what I will be doing this week: 5 sets of this – 1.5 minutes fast; 30 seconds recovery; 3 minutes fast; 60 seconds recovery. That’s only 30 minutes altogether, but it will be hard work!
And how about a home HIIT session? The great thing about this is that you don’t have to have any equipment. Sometimes I do skip or use a resistance band but not always. I have an interval timer app on my phone which is really useful. This is what I did today: 40 seconds activity followed by 20 seconds rest – 2 sets of: running with high knees on the spot; plank; right leg lunges (forward/back); left leg lunges as before; press ups; sit ups; jump squats; up/down plank; bridge; burpees. I hardly ever do the same routine for this and often change it as I go along depending on what I feel like!
There is quite a bit of evidence that short intense periods of exercise are as useful for fitness as longer, more gentle exercise. Here is an interesting link to Dr Michael Mosley’s findings about high intensity interval training.
I think interval training in running is not only a good way to make training more interesting , but also more efficient. And HIIT sessions are a great way to fit hard work exercise into short spaces in your day, and still know that it’s making a difference.
It’s only a few days until the Ealing Half marathon. I’m raising money for JDRF on this link. They fund research into a cure for Type 1 diabetes. Type 1 diabetes is an auto immune disease that typically manifests in childhood, and is a lifelong condition requiring several insulin injections a day and constant monitoring of blood glucose. It can lead to limb and life threatening complications. Let’s help find a cure! Thank you for all your support so far – I’ve only got 4 more half marathons to run in 2019!