Recently I’ve been tagged onto different articles on Facebook which claim that steady state cardio is bad for you, and that running on the treadmill for long durations every day will mess with your metabolic hormone, T3, and that if you’re aiming for weight loss, you should do no cardio at all. It’s interesting to read the different views on exercise by other “fitness professionals”. I do agree with a couple of points here and there, but I think that they have a very skewed view on people’s exercise goals. Not everyone is in it purely for weight loss (Not everyone should) and not everyone is in it purely for vanity (Yeah, some of us actually train to be fitter, faster and stronger). But since I am an avid marathon runner myself, this is my comment and humble opinion on cardio exercise. Before I begin, let’s just be specific. Assuming the goal is Weight Loss and the cardio workout is Running. Read on…
What is steady state cardio?
Steady state cardio is a term coined to describe a cardio workout that goes on continuously at a steady state of heart rate for a long duration. For the majority, the only steady state cardio one can achieve for a bout of 30 minutes is simply walking (~40-50% of max HR). To be able to sustain a steady state of 60% of max HR and higher, one would definitely have to train for it for quite a while to build up endurance. In one of the articles, spin class was given as an example, and I would definitely have to disagree with this one. Have you ever been in a spin class? There is NO WAY you maintain a steady state heart rate throughout that hour, if you were following the instructor correctly.
How do we lose fat?
Plenty of ways. We all know that the road to a slimmer, leaner you is a combination of exercise and good nutrition. The nutrition part of it is a bit complicated. I, myself, would refer to a dietician or a nutritionist every now and then to get my information right. But the exercise part, I can help break down for you.
Cardio is short for cardiovascular (anything relating to heart and blood vessels) and cardio exercises are any workouts that works out your heart. Your heart, like your other parts of the body, is a big muscle – the more you exercise it, the stronger it becomes. Unfortunately, it is buried deep underneath our ribs, so we can’t do dumbbell lifts with it. The only way to exercise it is to move your body fast enough so your heart starts to beat faster and you can imagine it contracting like a pump.
Resistance training encompasses any exercise using a load. It could be weights like dumbbells, barbells or machines, or it could be your own body weight (push ups, sit ups, squats). These exercises are aimed at increasing strength by working out your muscles. The more resistance training you do, the bigger the muscles your body will produce (via amino acids) to cope with the load, thus you become stronger.
Both types of exercise raises your heart rate. It all depends on intensity and repetition and duration. And as long as your heart rate is raised, and your muscles are contracting, you’re burning fat. Work yourself out hard enough, and you’ll experience Excessive Post-Exercise Oxygen Consumption (EPOC). Cardio – do short bursts of sprints. Resistance – either increase load or increase repetition and speed.
The T3 hormone and thyroidism
Some articles claim that long term steady state cardio impairs the production of T3 hormones. These hormones, coupled with T4, are thyroid hormones, produced to regulate your body’s metabolism. Hypothyroidism is a state of too little T3+T4, whereas hyperthyroidism is a state of too much.
I have personally been through hyperthyroidism. Twice. The first time it hit me, I was 20 years old, and it came quite suddenly. I couldn’t run. I was perpetually sweating and feeling hot. I lost plenty of weight. I couldn’t run. I couldn’t run. It was quite a stressful time for me because I was not performing well in any of my races and I felt extremely flustered. Have I been running consistently before I got it? Yes. I ran almost every day, ranging from 4 to 8 kms depending on what I felt like. If steady state cardio impairs the production of T3 hormones, how did I get hyperthyroidism from running every day? I read a few articles online and asked my doctor about it, and T3+T4 hormones, as hormones do, can be triggered by many possibilities. Diet, change in lifestyle, genes, stress…anything. My grandfather has the same problem, so I think for me it was in my genes (skipped a generation though) and I was in college then so possible stress and lifestyle change played a part too.
Here’s where it gets interesting (to me, at least). Can running make you fat? I really think chances of it are unlikely. Science has every proof that running, fast or slow, does not make you fat. Whether you’re going at 50% of your max HR or at 80%, you’re burning SOMETHING, how else do you get your energy to move? Newton’s law of conservation of energy states that energy cannot be created nor can it be destroyed. Your body has to burn something to get energy. And sure it may be burning up some proteins (muscle mass), but only if you have no other fuel to burn! Plus that takes forever to break down so you’ll be running very slowly if your body is fuelled by only protein. To run, your body burns up a mix of carbohydrates, fat and protein. The rule is, eat a well balanced diet and your body will know what to burn.
Is running a steady state cardio exercise? Only if you want it to be. I know a girl who beats me in every run since 2 years ago and when I asked her how she trains, she told me that because of her busy schedule, she can only do interval running. She trains about 30 minutes to an hour every other day, and when she runs a full marathon, she aces it at 3 hours 45 minutes. Is she fat? Far from it.
Where heart rate is concerned, I once wore a heart rate monitor on one of my marathons. (Many runners do actually, so you can ask them). I was told by my lecturer in Auckland university that marathoners run at about 85-95% of their max. I did not believe him. It seemed impossible to be running at such intensity for so long. So I tested myself. Wanna know what my heart rate was throughout the whole marathon? No lower than 165 bpm. That’s about 84.6% of my max at that time and I sustained it for a little over 4 hours. I didn’t believe it myself, but it’s true. Train hard enough and your cardiovascular endurance will amaze you.
High heart rate = high caloric burn. May not all be fats, but a good portion of it definitely was.
So lose weight, how?
As a personal trainer, if you tell me your goal is to lose weight, then I strongly believe in a a well balanced diet and cross training. Your body is amazing at adapting and finding the optimum efficiency so doing just one type of exercise will do you no good. Do a mix of cardio and resistance training. Throw in some weights if you like, or dance or yoga every once in a while. Build your fitness and strength up gradually and keep challenging yourself.
Don’t run for 2 hours on the treadmill at a fixed speed and gradient every day. Your body will adapt to that intensity and duration very fast, and when that happens, your caloric burn will be less (Not zero). Do that for a month and then raise the bar. Increase your speed, or throw in an uphill. Then go and do some burpees or squats at the side for some added resistance training.
But for the record, weight loss should NOT be your only goal in mind. Maybe you started off with that, but when you feel the difference and see the changes in your own strength and abilities, you should shift your goals to bigger things in life. Maybe you want to hike Mount Kinabalu? Maybe you want to travel with your partner for months and do plenty of walking? Maybe you want to go bungee jumping? I have always encouraged my friends and the people I train to enjoy their workouts. Running is the easiest sport to get in to, because all you need is a pair of shoes. And with the abundance of runs organized in Malaysia throughout the year, anyone can set a goal to run a 10, 21 or full marathon at any point in time and work towards it. The feeling you get from crossing the finish line for the very first time is priceless. Not to mention, addictive ;)