If you’re starting an exercise plan, you might be thinking it’s as easy as hopping on a treadmill and lifting some weights, but there’s more to it if you want to do it effectively.

When you start out, it’s a good idea to learn what your target heart rate should be and what the different zones of intensity are.

You should figure out what your target heart rate is so you know how hard you should be working out. Remember that the formula is an estimate. Heart rates are affected by genetics, fitness level, medications, stress hormones, respiratory health, illness and mental state. You may need to adjust your target range.

To measure your resting HR, take it first thing in the morning seated and breathing normally. Average this over several days. Resting HR will be higher if you are ill, sleep deprived or stressed.

Here’s the formula for finding your low and high target heart rate:

This equation is for a target heart rate of 50-85%, which is a good medium zone that – for most people – will land them in aerobic/threshold training zones. If you’re new to working out, aim for the lower half, if you’re a seasoned exerciser, train in the upper half of the range. At TMC Cardiac Rehabilitation, we use a target range of 40-80%, which is challenging enough to get positive structural adaptions to exercise without creating unnecessary risk.

“We want to challenge the heart, but not make the exercise so hard that it deprives the heart muscle itself of oxygen,” said Sabine Harrington, exercise physiologist at TMC Cardiac Rehabilitation.

Each person has unique physiology, including their own heart rate zones 1-5. Fitness devices can give you an estimate of what your heart rate is and which zone you fall into, but you can also gauge with your breathing.  

“Breathing doesn’t lie because it is a direct result of carbon dioxide building up in your blood stream as metabolic rate increases,” Harrington said. “Heavy breathing usually indicates heavy workload. Even if your heart rate isn’t in your target, if you are breathing faster and deeper but don’t feel out of breath, it means you are doing metabolic work. Aside from congestive heart failure exacerbation, asthma and other pulmonary conditions, breathing frequency should parallel exercise intensity."

Here's an idea of each zone:

Zone 1: Warmup/recovery.

This zone delivers more O2 to the tissues than it consumes and facilitates the removal of metabolic waste products and immune cell distribution.

Zone 2: Beginning of exercise.
You can carry on this type of light exercise for a long time and can often hold a conversation at the same time. Mitochondrial density and vasculogenesis (formation of new blood vessels) occur at this zone. This is laying the structural foundation for a more efficient metabolism, improving the ability of your cells to burn fat as fuel and increasing insulin sensitivity, both at rest and during exercise. This is a biomarker of longevity.

Zone 3: Medium intensity
During this zone your body increases the strength of cardiac muscle, respiratory muscles, and other large muscle groups that you recruit while doing your activity (running, biking, swimming, etc.) Zone 3, like zone 2, can be considered "aerobic" exercise.

Zone 4: Increased difficulty.
It will be hard to carry on a conversation. This zone causes increases in enzymatic buffering capacity of lactic acid (i.e. lactate threshold). This is also most likely where your body shifts to using carbohydrates, rather than fat, as more than 50% of it's energy substrate. The more carbohydrate burned, the more CO2 produced, and the faster your body has to breathe to get rid of it. This is sometimes called "anaerobic training" (meaning without O2), even though O2 is still being utilized, but at a rate that the body is outpacing. This intensity may be contraindicated for higher risk cardiac/pulmonary conditions.

Zone 5: Maximal intensity

Most of us will not reach unless forced to! This intensity should be reserved for individuals who have already been regularly exercising and have already "built their base" of zone 2 and 3 work. This intensity may be contraindicated for higher risk cardiac/pulmonary conditions. This is the intensity where "VO2 max", or the maximal rate of O2 consumption, is achieved. Mitochondrial density and blood vessel building also happen at this zone. It is also the zone of peak carbohydrate usage, so remember to refuel with healthy fat, protein, and carbohydrate.

--

 Need a primary care provider? Visit tmcone.com. With more than 20 convenient locations throughout Tucson, TMCOne has a provider for everyone in your family. We look forward to being your partner in care.