Heart Rate Training: Cross-Training


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Cross-training can be quite an education for an HRM user. You've probably spent time fine-tuning ideal heart rate bands for your various running sessions, to the point where keeping to them is almost second nature. But when you climb into a pool or onto a bike, say, you find that none of your readings makes sense.

From a practical point of view it couldn't be easier to use your HRM in cross-training. All the main models are waterproof to at least three metres, it's easy to attach the watch to the handlebars of a bike or rowing machine, and you can even use your own chest strap to transmit your heart rate to a piece of gym equipment with a built-in monitor, as all the models use the same frequency.

It's when you start getting active that you need to be armed with a little extra information.

If you're aquarunning or swimming, for example, it's likely that your heart rates for a given effort are going to be much lower than those you're used to from running, even though you're using the same muscles. Your maximum heart rate here will probably be about 12 beats per minute lower than your treadmill max, and so your training heart rates will be out by a similar amount. The main reason for this is the cooling effect of the water, but the fact that your bodyweight is supported in the pool is also significant.

As you don't have any mile markers in aquarunning, your heart rate is the only objective reflection of how hard you're working, and this can be particularly useful when you're new to an activity and don't know how your muscles should be feeling. Aim to keep your heart rate sensibly low.

If you do high-intensity sessions, keep them short, as you would in running. Remember that your muscles will be working disproportionately hard, something you should especially bear in mind if you're cross-training after an injury. Even if you're not injured, repeatedly overworking your muscles will at the very least cause lactate to accumulate and diminish your aerobic capacity.

While it's important to keep up some high-intensity work so that you maintain your VO2max, don't forget that no matter how hard you try, you'll struggle to hit high heart rates in most forms of cross-training.

Cycling and rowing again give you lower heart rate levels than running, despite the fact that you're exercising hard. This is once more because your bodyweight is being supported, though the fact that you're using different muscles from running also contributes. On a bike, work at least 10 beats below your normal running levels, and if you're not used to cycling, keep your heart rate even lower. As you get more bike miles under your belt, you'll see your maximal and training heart rate values rise because of your improved ability to supply more blood to the specific working muscles. Nonetheless, only highly trained cyclists find that their heart rates when cycling ever approach those they achieve when running.

You'll find the situation the same in circuit training: unless you do particularly long sessions of a moderate to hard intensity, you'll struggle to get high heart rates. It's once more simply better to accept lower heart rates and, here, to use your HRM as a form of monitoring rather than a means of control.

If you cross-train with a stepping machine or aerobic dance, however, you're having to carry your own bodyweight and you're using many of the muscles you use to run. Your heart rates in these cases will be quite similar to when you're running, and it's therefore not surprising that both activities have been found to improve running endurance.

These two are rarities. The key fact to remember is that most forms of cross-training support your bodyweight and so will cause your heart rates to be lower than when you're running, even if you do the activity regularly. If you're only cross-training occasionally, use heart rates 10-15bpm below your usual levels as a starting guide and adapt them as necessary. If, however, it's going to be a more regular feature on your schedule, you should start to use your monitor to work out sensible heart rate limits for different types of session of a particular activity, as you did for running. Here, more than ever, your monitor should be helping to protect you against overtraining.