Breathing and Heart Rate Control
By Dr. Tom Seabourne
If you ever learned to play a wind instrument, then you probably know how to breathe from your diaphragm. When you exhale, a hand placed on your stomach moves toward your backbone. Your abdomen expands on your inhalation. This is called reverse breathing. Most folks breathe the opposite way. They inhale and their chest expands while their abdomen contracts. This is termed thoracic breathing. Nothing is as healthy as reverse, or diaphragmatic, breathing which allows the air in the bottom of your lungs to be efficiently transported out and replaced by fresh air.
Breathing is subtle, yet quite extraordinary. It takes mindfulness to find it. And although breathing is normally involuntary, an act of will can slow it down or speed it up; make it long and diaphragmatic, or short and thoracic. Breathing is a present-time, mindful process. It is always happening, right now. You cannot be fondling memories or planning your future when you’re contemplating your breath. Observe your breath, and you are automatically in the present. You are in the here-and-now.
One breathing strategy is to pay attention to the sensations as air passes through your nostrils. Inhale through your nose. Notice the point just inside your nose where you have the most powerful sensation of air flow. Exhale and feel the sensation again. Focus your attention on this spot. Use this single point to keep your attention fixed. Don’t try any specific breathing techniques. Just watch your breath. Although you control the pace of your inhalation-exhalation cycle, let your breathing proceed at its natural pace. Sometimes it slows, speeds up, is deep, short, or choppy. Just observe. And watch how thoughts inadvertently affect your breathing. Each time though, come back to the object of your focus-your breath.
At the beginning of your inhalation, follow your breath just for that inhalation. Then, at the start of your exhalation, follow your breath just for that exhalation. Focus on a single breath cycle. Forget about the last breath, and don’t think about the next one.
There are a variety of psychological and physiological factors that affect your heart rate. The pace of your heart is unique to your body. It is self-regulating. You don’t have to do a thing and it keeps beating. It maintains its own rhythm to keep you alive. But your hormonal responses and your central nervous system (CNS) and autonomic nervous system (ANS) can affect the speed and rhythm of your heart. Your hormones send chemicals into your blood to affect your heart’s pace. And your heart beats faster or slower depending on how your nerves stimulate your heart.
While reading this passage, imagine your spouse or a good friend tapping you on your shoulder. External input from your nerves and hormones automatically increase your heart rate. Or, think back to when you were driving your car and somebody cut you off. Your heart raced uncontrollably although you were just sitting quietly (or not so quietly). Mindfulness allows you to predict and override a conditioned physiological response-that is, it allows you to regulate your heart rate when you are threatened and handle any situation appropriately.
The medulla of your brain is your control center for your heart rate. It either speeds or slows your beats per minute. Your ANS has two components: Your sympathetic nervous system (SNS) and parasympathetic nervous system (PNS). Your SNS speeds your heart rate by releasing hormones and chemicals called norepinephrine, epinephrine, and catecholamines. When your heart rate increases to a frenzy this is termed tachycardia. There are no cardiovascular benefits when your sympathetic nervous system increases your heart rate. It is simply your hormones sending stimulating chemicals to your heart, and nerves directly affecting your heart to respond to an emergency.
Your PNS is in your brain stem. This is the area that slows your heart rate. A chemical that your PNS releases to slow your heart rate is called acetylcholine. When your heart rate slows, you experience bradycardia. Yogis can slow their heart rates to the less than 20 beats per minute (BPM). And the famous magician, Harry Houdini was able to survive in a coffin-sized airtight box for hours.
Your nerves and hormones together regulate your heart rate when you are moving, and when you are still. As you begin training, your heart rate speeds up because your PNS is inhibited. That is, the mechanisms that slow your heart are essentially turned off, and your BPM naturally increases. Other factors besides exercise that affect the pace of your heart include blood sugar levels, different foods, lack of sleep, anxiety, fear, and anger. Chronic nervousness, sometimes referred to as “trait anxiety” can cause your heart rate to remain elevated for extended periods.
The better shape you’re in, the slower your heart rate, right? Not necessarily. Professional tennis player Bjorn Borg owned a resting heart rate of 35 BPM. Now that makes sense because Borg was an elite athlete. But Olympic marathon superstar Frank Shorter’s resting heart rate was 175 BPM. Your genes account for about 50% of what your maximum heart rate will turn out to be. Smaller hearts beat faster than larger ones. But heart rate is not affected by your bodyfat percentage or your body type. In general, the more fit you are, the stronger your heart beat (stroke volume). In other words, fitness determines heartbeat strength and duration.
If you are tired, on medication, are under stress, at high altitude, or in high humidity, your heart rate may change. Therefore, be mindful of environmental factors. And if you are performing high intensity activity, your sympathetic nervous system increases your heart rate by directly stimulating nerves. Years of physical training increases your parasympathetic nervous slowdown by stimulating your vagus nerve. Your vagus nerve is responsible for slowing your heart rate. This is the training effect discussed earlier. With increased vagal stimulation, your heart rate slows to bradycardia when you are not working out.
During exercise, your CNS is the most influential factor determining your heart rate. When you tie your running shoes, your CNS sends messages to your medulla to prepare for activity. But your heart rate increases even before you begin your training. Just by anticipating a workout, your heart rate can increase as much as 100%. Does this mean you can get all the benefits of exercise, just by thinking of it? Not yet. Until then, go out there and use your heart to get fit.