Much of the benefits from heart rate training involve the body's energy systems and one of these systems is responsible for the long term supply of energy to your working muscles.

Fat is an abundant source of energy for the endurance athlete. Training within this heart rate zone - best accomplished by doing long, slow ergos, (or runs or water-work) - develops the body's ability to feed the working muscles more efficiently.

The other major advantage to training in this zone is weight loss, because you are almost exclusively burning FAT. You will also be allowing your muscles to re-energize with glycogen, which has been expended during those faster paced work-outs.

Underestimate this training zone at your peril.

When you train in this Heart Rate zone, you are training your cardiovascular system. Within this range, the body's ability to transport oxygen to, and carbon dioxide away from, the working muscles can be developed and improved.

As you become fitter and stronger from training in this zone you will get the benefits of some fat burning and improved aerobic capacity. 75% training often feels good.

This zone is also ideal for developing local muscle strength.

This is the zone in which an enormous amount of benefit can be gained.

Somewhere between 80 and 90%, your individual anaerobic threshold is hiding. Between these heart rates, you use very little fat, instead you start to use glycogen - which is stored in your muscles - as the main source of energy.

Unfortunately, one of the by-products of burning this glycogen, is the rower's worst enemy, Lactic Acid.

There is a point at which the working muscles are producing lactic acid at a faster rate than the body can remove it. The heart rate this happens at, depends on you as an individual but when you do hit this point - known as Anabolic Threshold it will be accompanied by a rapid rise in heart rate and a slowing of your pace - sound familiar?

Through the correct training it is possible to delay the Anabolic Threshold either:
by increasing the heart rate at which you reach it or
by increasing your body's ability to deal with the lactic acid for a longer period of time.

The fitter you are the nearer you will be racing to your Anabolic Threshold. But beware, pulling a 1:45 split does not mean you are rowing at your Anabolic Threshold if the training you have been under-going is incorrect.

Assuming you are fit you will be racing at just below, or right on, your AT (depending on the length of the race). Sometimes elite athletes can hold a pace above their AT but for most mere mortals "going off too hard" will only result in you "blowing up" half way through a race - something most of us have experienced at some stage, and it's not pleasant.

In this zone you will only be able to train for short periods of time. It effectively trains your fast twitch muscle fibers and helps to develop speed.

It is worth being aware that to develop this speed you must first have developed your ability to deal with lactic acid.

This zone is reserved for racing sprints and only the very fit are able to train effectively within the red line zone.

Remember, training very near your maximum HR can be dangerous.