One of the most frequent questions I hear asked with regards to cardio is “how do I know if I’m working hard enough?” Despite the number of times I’ve heard people ask this the answer is almost never the same.
The biggest hurdle on the road to answering such a question is personal fitness level. Everyone’s fitness level is unique in a multitude of different ways, and training goals should be equally varied. As you spend more and more time training your own experience will quickly trump any advice you can find in a blog or forum post, but beginners can benefit greatly from some general guidelines regarding early training concerns.
(Or, “The Couch-to-5k’er”)
To be concise: just finish. If you’re brand new to cardio training you should have one goal and one goal only; to complete your desired run time without having to walk. 20 minutes is a good starting goal, so aim for something around there. Once you can run 20 minutes without stopping, you can start to worry about speed and distance. Until then, just work towards getting comfortable with an easy 20 minutes 3 or so times a week.
Once you are able to spend 20 minutes running 3 times a week you can start to concern yourself with distance a bit more. Evaluate your goals and pick a distance to train for. Most people start with 5 or 10km runs as their goals, since many “fun runs” (which are popular reasons to start training) are one of those two distances.
At this point your training does not need to be too structured (although it you work better with strict structure that’s fine, and there are about a million training plans on google you can use) as you should mostly be trying to simply add a bit of distance each week until you can complete your target run without stopping. Once you can run at least 5km without a walk-break it’s time to switch gears a bit and take our first real look at intensity.
Once you’re able to comfortably run 5km you can start to concern yourself with just how fast you’re running, and how hard you’re working. Up until now we’ve mostly been working on getting you comfortable with regular cardio, and creating a base fitness level so that you are physically ready to start working your body a bit more strenuously.
If I had to put your new training philosophy into a single ‘googleable’ phrase I’d pick “anaerobic threshold.” Your anaerobic threshold is the point at which your body switches from aerobic to anaerobic work. That is to say, the point at which your body can no longer supply sufficient oxygen to your muscles to allow them to continue working at their current level of intensity. If you’re below this threshold you can keep working as long as your fuel stores, (and willpower!) hold out. Train above it and it is simply a matter of time until you are forced to stop due to a lack of oxygen (and/or an excess of waste) in your muscles.
What does this mean? To put it simply, it means run as hard as you can maintain for the entire duration of your run. Finding the sweet spot where you can keep working through the burning legs and lungs takes time, so don’t try and force it too soon. The delicate balancing act of playing chicken you’re your anaerobic threshold requires practice, and paying keen attention to the feedback your body is giving you. Take your time and work towards maintaining that just-under-the-wire feeling for longer and longer. It takes a lot of guts, but more than that it required patience and care to avoid hurting yourself.
Not a runner? Not a problem!
The same principals apply to all forms of cardio, just with sport-specific time and distance goals. Practice the kind of cardio you enjoy and want to get better at, and with time you will see similar cardiovascular growth. Swimming, biking, running, hiking, whatever works for you; it’s all good!
Just remember, start by getting comfortable with a moderate time frame for the exercise. Once you feel good doing a bit of work a few times a week, find a good goal distance for your sport. Once you can finish that distance you will have a reasonably resilient body, and you can start looking at intensity to improve the quality of your workouts.