Picking up from where we left off, we’re going to talk about the MOST vital organ in the human body – the HEART!
Heart Rate (HR)
Our hearts are constantly beating (to pump oxygenated blood around the body) to keep us alive. Heart rate is usually expressed in BPM (beats per minute). The rate at which the heart beats varies for every individual. This is why the resting heart rate (RHR) of an individual is a good indicator of cardiorespiratory fitness. The resting heart rate is the number of times the heart beats per minute while it is at rest. The more physically fit you are, the stronger your heart is, which results in a lower resting heart rate. A strong heart is able to pump more blood around the body with each beat (therefore, your heart rate decreases).
The whole point of exercising is to raise your heart rate (to stress it enough to elicit change and adaptation). You can see why knowing your heart rate and how it responds to exercise is one of the keys to fitness.
Measuring your Resting Heart Rate (RHR)
The best time to accurately measure your resting heart rate is the moment you get out of bed. Make sure you wake up peacefully and not by the buzz of the alarm or the thought that you are late for work. This may lead to inaccurate readings because your heart rate probably shot up 100 beats to cope with the stress (Ok, kidding!). But yes, it will affect your resting heart rate.
You can use a heart rate monitor/watch (what I do) or do it the old-school way – manual palpation.
-Place your index and middle fingers on the radial artery (as shown in picture)
-Set your timer for 60 seconds and start counting!
-Take your average readings over 3 days and voila, you have your resting heart rate (RHR)!
The normal range: 60-100 beats per minute 
Don’t be alarmed if your resting heart rate falls below the normal range (my resting heart rate is between 48-51 BPM). I am sure many of my crazy running friends are well below that range too! Well-trained athletes have resting heart rates that can go as low as 40 beats per minute!
*The resting heart rate is influenced by many variables – stress, drugs and medication, caffeine, body composition, fatigue, fitness level etc. Make sure that you are not on any drugs for at least 12 hours prior to taking your resting heart rate.
*Your resting heart rate (RHR) provides an insight into overtraining syndrome. If you have an elevated RHR of over 5bpm (over a few days), it is time to schedule in REST.
Maximum Heart Rate (MHR)
The most accurate way to determine your maximum heart rate is to undergo a physical test at a physiology lab. But not everyone has access to these facilities so here are a few alternatives:
-Fox, Naughton & Haskell Formula: 220 – age = Maximum Heart Rate
-Tanaka, Monahan & Seals Formula: 208 – (0.7 x age) = Maximum Heart Rate
-Gellish et al. Formula: 206.9 – (0.67 x age) = Maximum Heart Rate
Adapted from the ACE Personal Trainer Manual, 4th edition, ACE (2010)
Please note that these formulas are a rough guide. Your maximum heart rate may differ by 7-12 beats on either side of the value.
Heart Rate Training
Hitting the Target
So how do you know whether or not you’re doing too much or not enough? You certainly do not want to over- or under exercise.
The next thing you want to know is: the right heart rate zones that you should be training in.
Heart Rate Zones
Most heart rate zones are calculated using the percentage of your own maximum heart rate. There are actually many limitations that come with this method because it doesn’t take into account the resting heart rate. Remember how the fitter you are, the lower your resting heart rate is? Again, I will leave that for another post. This should suffice for now.
Let’s take a look at the different zones:
Zone 1: Very Light
About 50-60% of your Maximum Heart Rate
Training in this zone improves blood circulation. Your heart rate is probably here if you’re taking a stroll in the park, walking your dog or shopping.
Zone 2: Light
About 60-70% of your Maximum Heart Rate
Training in this zone also improves blood circulation. This zone is ideal for warm ups, cool downs and recovery periods after a hard workout. If you’ve ever heard of LISS (Low Intensity Steady State training), this is the zone to be doing just that.
If you’ve just started your fitness journey, you can spend about 30 minutes in this zone. It helps to build a good stable aerobic base with HEALTH as the primary goal.
Activities in this zone include: recovery runs, jogging, brisk walking, power walks etc. This zone is also known as the “fat burning zone” because you’re mainly using FAT as fuel. This zone is pretty much aerobic and fat metabolism requires oxygen. However, if you are talking about fat loss, this is not the ideal zone to be training in (it gets complicated). I can elaborate on that in another post so we’ll leave it at that for now.
Zone 3: Moderate
About 70-80% of your Maximum Heart Rate
Zone 3 is where you perform your easy runs. You can comfortably hold a conversation when you’re running/working out in this zone. This is where you’re able to work on general fitness and build up on endurance.
You will burn both carbohydrates and fats in this zone. Lactic acid slowly rises in this zone but your body is able to clear it efficiently.
Zone 4: Hard
About 80-90% of your Maximum Heart Rate
This zone is where your anaerobic limit is at. It is where you perform your tempo/threshold runs.
These runs are done at your lactate threshold, the highest speed at which your blood lactate levels remain steady. It places just enough stress for the body to raise the lactate threshold. Tempo runs prepare the body and the mind to adapt to hard running over longer distances. It also works to build on endurance and helps the body delay fatigue caused by lactic acid.
Working out in this zone should feel comfortably hard.
Zone 5: Maximum Effort!
About 90-100% of your Maximum Heart Rate
What most people term as “ALL OUT”. If you are performing interval runs, this is THE zone – MAXIMUM! It is a pretty tough zone to be in and it is usually attained by trained athletes. This zone can only be sustained for short periods of time such as doing 400m sprints.
Interval runs improve your VO2 max – the maximum volume of oxygen that your blood can deliver to your muscles when running at high speed. This type of training aims to increase tolerance against lactic acid build up and allows lactic acid to be cleared more efficiently. This results in improved speed and performance.
If you have just started out, don’t worry about not being able to hit this zone. Be patient.
To Sum it All Up
Being aware of your training intensity (by knowing your exercise heart rate DURING the workout) helps you determine when to slow down, maintain or kick it up a notch!
Get a Heart Rate Monitor
I am currently using the MIO Alpha 2 (www.mioglobal.com). It is an idiot proof watch that does all the work for me (well, except the running). It accurately detects my resting heart rate and exercise heart rate. I just have to make sure that I hit the right heart rate zone!
Use these tools to determine your resting heart rate (RHR), maximum heart rate (MHR)and the appropriate zones that you need to be training in to maximise your fitness goals!