IT’S ABOUT YOUR HEART

By John Hofman

According to a study performed at the Illinois Fire Service Institute, three hours of prolonged firefighting stiffens arteries and impairs heart function in young healthy male firefighters. So what does that mean to you?

Ok, let’s not all panic just yet, but rather break this information down to see how we help our firefighters better protect themselves. The same things occur in athletes who perform maximal aerobic or heavy resistance exercises (hence the phrase tactical athlete). It is worth noting that the majority of sudden cardiac deaths during exercise occur in athletes with existing cardiovascular disease, and if we looked at firefighters, the same could be assumed. In young athletes (under 35), sudden cardiac death is caused mainly by inherited structural and functional abnormalities, while in the over-35s it can be attributed primarily to coronary artery disease. Both of these conditions can be diagnosed through preventative screening.

Yet as Bo Fernhall states, “Usually a stiff artery is associated with an increase in inflammation and blood pressure, but we didn’t find any increase in either of those during our study.” You are probably asking yourself how this relates to you. Well, we know heart attacks are one of the leading causes of death among firefighters, and many times when we go to the doctor we get our cholesterol checked, but what about your C-REACTIVE Protein?

C-reactive-protein, is a marker measuring the intensity of early inflammation in Myocardial Infarction, which predicts long-term mortality and heart failure. In fact, studies have shown that it could be a better predictor because it provides analytical information beyond that provided by conventional risk factors and the degree of left ventricular systolic dysfunction (it has also been linked to Alzheimer’s disease and dementia).

What we do know from this study is that artery stiffness and cardiac fatigues did occur. So let’s take a look at healthy hearts (instead of the usual unhealthy). It has been shown that exercise-induced cardiac fatigue, or a reduction of cardiac function, occurs following prolonged strenuous exercise. In a study carried out in the 1960s, athletes were found to exhibit a significant decrease in stroke volume (the amount of blood pumped out by the heart in a single beat) following a bout of prolonged exercise – THE SAME WAS PROVEN DURING FIREFIGHTING. This established a possible link between exhaustive exercise and the potential for a decrease in cardiac function. Makes sense, right? After all, if skeletal muscle fatigues after a period of extended exercise, why not cardiac muscle too? But WAIT THE HEART CAN’T REST….it has to supply the body with blood, if it took a “break” we would die.

I know what you are thinking “I do not perform ultra-marathons, or train to complete exhaustion” so I will be fine. Maybe, but cardiac fatigue has been demonstrated in healthy subjects following a 20km run and a 60-minute cycle ride. So it is possible that cardiac fatigue may affect firefighters as well as the elite athletes taking part in ultra-endurance events. Why? Athletes spend months preparing for their event, whereas many firefighters do not value the importance of continued fitness and therefore exhibit several of the risk factors for cardiovascular disease, including being overweight and having elevated blood pressure and/or cholesterol. Now include the actual physical and psychological stressors involved with the job – heat stress exacerbated by heavy gear that doesn’t allow the body to cool, acute periods of aerobic and resistance exercise, and activation of the “fight or flight” response of the sympathetic nervous system, and you are asking for trouble.

It is worth noting, that there is no evidence to support the existence of cardiac fatigue following periods of intense brief exercise (read my articles on interval training). In studies of relatively short periods of endurance exercise (50-150 min), cardiac fatigue has not always been observed. As a result, it has been suggested that exercise duration may be an important factor in determining the onset of cardiac fatigue, although the existence of a serious ‘threshold’ has not been established. Other factors, such as temperature and humidity, altitude, hydration status, gender and age may also be significant, and differences in these variables may account for some of the conflicting findings in the current literature.

This does not mean you should go out and throw your sneakers away and lay back on the recliner. A regular endurance training program, will in fact, ultimately benefit the heart and reduce the risk of major heart disease in the long-term. However, it is important to remind people embarking on an intensive training program (especially sedentary firefighters) that it is advisable to undergo a full cardiovascular screening and to take a sensible approach towards an exercise program. Based on the results of the Illinois Fire Service Institute study, it is not known whether the results increase the risk of a firefighter having a heart attack or not. HOWEVER, it was discovered that the firefighter’s endothelial function – blood flow as controlled by the inner lining of blood vessels – improved after the firefighting exercise. This is generally seen in athletes who perform heavy resistance exercises. Why did this occur? As Fernhall states “Firefighters do a lot of resistance-type exercise when they’re fighting a fire – handling heavy equipment, doing forcible entry and other tasks that increase blood flow in their arms, which is where we measured endothelial functioning”. Endothelial dysfunction is emerging as a significant complication for a person battling Type 1 Diabetes.

QUICK TIPS

One recent study performed at the Institute of Health Science and Applied Physiology showed that cardio after weight lifting seemed to cure the arterial stiffness issue – to help combat arterial stiffness perform aerobic training after resistance training. The study also found that not all heavy resistance training “Cardiovascular responses to short-term Olympic style weight-training in young men” found that their systolic – actually decreased. Another similar study found that weight training decreased diastolic blood pressure, raised HDL, lowered cholesterol and decreased insulin levels, all big risk factors for heart disease. Cardiac fatigue has not always been seen in short periods of endurance exercise (50-150 min), so use a sensible approach to exercise.

C-REACTIVE PROTEIN

• You are at low risk of developing cardiovascular disease if your hs-CRP level is lower than 1.0mg/L
• You are at average risk of developing cardiovascular disease if your levels are between 1.0 and 3.0 mg/L
• You are at high risk for cardiovascular disease if your hs-CRP level is higher than 3.0 mg/L
  
  Coach John Hofman, MS., CSCS*D, TSAC-F*D is one of leading experts in the field of Firefighter Health and Wellness and currently serves as the Director of Tactical Strength & Conditioning Specialist for Southern California University Health Systems. Prior to going SCU, Coach Hofman spent 10 years as the strength and conditioning coach for the Sacramento Fire Department, where he oversaw the Wellness Centre, coordinated the department’s medical and fitness assessments, developed recruit fitness training, pre-employment medical and fitness evaluations and assisted with the department’s 20-certified Peer Fitness Trainers. In addition, Coach Hofman was the 2018 recipient of the National Strength and Conditioning Association TSAC Practitioner of the year Award. This award is given to a TSAC educator and practitioner who has made noteworthy contribution to the teaching and practical application in the field of tactical strength training and conditioning. 

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