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CrossFitters should check their blood pressure monthly. Thirty percent of the Dutch population has high blood pressure, even seemingly fit people. High blood pressure increases the risk for cardiovascular diseases, such as a heart attack. Because it is hardly accompanied by symptoms, high blood pressure is an unnoticed risk, especially during “blood pressure increasing sports” such as CrossFit.
Unnoticed risk from the age of 40
From the age of 40, the risk of having high blood pressure (hypertension) increases. Even if you are super fit, eat healthy and exercise regularly.
High blood pressure is hardly accompanied by symptoms and therefore often goes unnoticed for years. Only when it is severely elevated, symptoms such as headaches, fatigue, nausea, shortness of breath and restlessness may occur.[1] This implies that seemingly healthy fit people can be at risk for a stroke, heart attack, heart failure, brain hemorrhage and sudden death, without being aware of it.
Blood pressure can fluctuate during the day and can be influenced by several factors such as thoughts, emotions, and power sports such as CrossFit. During a CrossFit workout, the heart rate, blood pressure and cardiac output (how much blood the heart pumps out every minute) temporarily increase significantly. Heavy strength training can even lead to very high pressure (>300 mmHg), which can be potentially dangerous.[2] If a person already has high blood pressure, imagine what can happen during a workout. [3] Therefor, regular measurements of blood pressure are crucial for CrossFitters, especially after the age of 40.
Measuring blood pressure
Blood pressure is measured with blood pressure meters. You can do this at home, at the doctor, or at your CrossFit box. The measurement gives two numbers: the upper and the lower pressure. The upper pressure (or systolic pressure) is the maximum pressure that builds up in the aorta, the body's main artery, when the left ventricle of the heart contracts. The lower pressure (or diastolic pressure) is the minimum pressure between two contractions of the heart, when the heart relaxes and the left ventricle refills with blood.[4]
According to the Dutch Heart Foundation, the ideal blood pressure is 120/80 mmHg. Research shows a linear relationship between a decrease in the risk of cardiovascular mortality and a decrease in blood pressure to a systolic blood pressure of below 115 mmHg and a diastolic blood pressure of below 75 mmHg.[5] A blood pressure of 135/85 mmHg is considered high and 180/110 mmHg is considered a severely increased blood pressure.[6]
A decrease of 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure already halves the risk of cardiovascular mortality. This means a person with systolic blood pressure of 120 mmHg has 50% less risk of dying of a heart attack compared to a person with systolic blood pressure of 140 mmHg.[7]
Causes and risk factors
There are two types of high blood pressure: Primary hypertension, where there is no clear cause, and secondary hypertension caused by an underlying condition such as sleep apnea, diabetes and thyroid problems, or by the use of drugs such as birth control pills, pain relievers and amphetamines. Over 90% of the cases concerns primary hypertension.[8]
There are several risk factors for hypertension, such as age, race and lifestyle [9]:
- The risk of hypertension increases by the age of 40
- Hypertension is more common among people of African heritage
- Hypertension seems to be genetic
- Overweight/ obesity requires more blood to supply body tissue. The more blood flows through your vessels, the more pressure there is on your artery walls
- People who do not exercise have a higher (resting) heart rate. This means the heart needs to pump harder, creating more force on the arteries
- Smoking immediately increases blood pressure temporarily. In the longer run smoking causes narrowing of the arteries, increasing the risk of heart disease
- Eating too much salty food causes retain of body fluids, which increases blood pressure
- Eating too little potassium can lead to a buildup of sodium in the blood. Potassium helps to balance sodium in the body, crucial for heart health.
- Too much alcohol damages the heart and increase blood pressure
- Prolonged stress can lead to increasing blood pressure and even to sudden death
Benefits of exercise on blood pressure
Although during a workout, blood pressure temporarily increases, in the long run exercising regularly has positive effects on blood pressure for people with healthy blood pressure and those with high blood pressure.
Directly after physical activity, blood pressure decreases (on average 15 mmHg systolic and 4 mmHg dialostic). This effect can last for 22 hours after the activity and is comparable to the effects of blood pressure lowering medication. In the long run, this lowers the risk of strokes by an estimated 30% and the risk of ischemic cardiac death by 30%. A reduction in systolic blood pressure of 2 mmHg reduces stroke mortality by 10% and ischemic cardiac death mortality by 7% among middle-aged people. [10]. And, as already mentioned: a decrease of 20 mmHg in systolic blood pressure or 10 mmHg in diastolic blood pressure halves the risk of cardiovascular mortality.
Furthermore, by working out regularly, cardiac remodeling takes place. The left ventricular wall, one component of the heart, thickens and its cavity size and function increase.[11] The left ventricle has the most important job of all components of the heart. It pumps oxygenated blood throughout the whole body. If the left ventricle loses its pumping power, the flow of oxygenated blood comes to a halt. If it takes longer than six minutes, the consequences can be very serious.[12]
Nice to know is that endurance training (cycling), as well as dynamic resistance training (squats), and isometric resistance training (plank holds) all lower systolic and diastolic pressure. Combined training lowers only diastolic pressure. [13]. Isometric resistance training has the potential for the largest reductions in systolic pressure. Isometric exercise for less than 1 hour per week can reduce systolic blood pressure up to 10 mmHg and diastolic blood pressure up to almost 7 mmHg. Isometric exercise, even handgrip training, induces changes in blood pressure that are similar to those achieved with medication.[14]
Recommendations
1. When you are over 40 and participate in power sports such as CrossFit, have your blood pressure checked regularly, even if you do not experience any symptoms
2. When you have one or more of the risk factors for hypertension and/ or your blood pressure is higher than 180/105 mmHG and/ or you exercise irregular, consult a medical specialist before participating in exercise, especially in CrossFit and weight training.
3. Try to live a healthy life as much as possible:
· Strive for a healthy body weight
· Eat at least 450 grams of vegetables per day, for potassium and fiber (Weightloss with fiber), and minimize the intake of red meat (How bad is eating meat?)
· Exercise regularly and consistently
· Stop smoking and maximize your alcohol intake to one glass per day
· Maximize your salt intake to 6 grams per day. Be aware of high salt products such as processed food and bread (How articifial is your food?)
· Eat potatoes, meat, fish, nuts and dairy for potassium. The advised daily intake is 3,5 grams per day for adults (one small piece of steak contains 0,4 grams).[15]
· Minimize stress!
Create your own health!©
References
[1] www.hartstichting.nl. Consulted July 5th, 2022
[2] Pedersen, B.K. (2015). Exercise as medicine. Evidence for prescribing exercise as therapy in 26 different chronic diseases. Scandinavian Journal of Medicine & Science in Sports.
[3] Niebauer, Josef & Borjesson, Mats & Carré, François & Caselli, Stefano & Palatini, Paolo & Quattrini, Filippo & Serratosa, Luis & Adami, Paolo Emilio & Biffi, Alessandro & Pressler, Axel & Schmied, Christian & Buuren, Frank & Panhuyzen-Goedkoop, Nicole & Solberg, Erik & Halle, Martin & LaGerche, Andre & Papadakis, Michael & Sharma, Sanjay & Pelliccia, Antonio. (2018). Recommendations for participation in competitive sports of athletes with arterial hypertension: a position statement from the sportscardiology section of the European Association of Preventive Cardiology (EAPC). European heart journal. 39. 10.1093/eurheartj/ehy511.
[4] https://www.umcutrecht.nl/nl/ziekenhuis/ziekte/hoge-bloeddruk; https://www.allesoversport.nl/thema/gezonde-leefstijl/bewegen-voor-een-betere-bloeddruk/. Consulted July 5th, 2022
[5] Pedersen, B.K. (2015). Exercise as medicine. Evidence for prescribing exercise as therapy in 26 different chronic diseases. Scandinavian Journal of Medicine & Science in Sports.
[6] https://www.hartstichting.nl/risicofactoren/gids-bloeddruk/bloeddrukwaarden. Consulted July 5th, 2022
[7] same
[8] https://www.mayoclinic.org/diseases-conditions/high-blood-pressure/symptoms-causes/syc-20373410. Consulted July 5th, 2022
[9] same
[10] Pedersen, B.K. (2015). Exercise as medicine. Evidence for prescribing exercise as therapy in 26 different chronic diseases. Scandinavian Journal of Medicine & Science in Sports.
[11] Niebauer, Josef & Borjesson, Mats & Carré, François & Caselli, Stefano & Palatini, Paolo & Quattrini, Filippo & Serratosa, Luis & Adami, Paolo Emilio & Biffi, Alessandro & Pressler, Axel & Schmied, Christian & Buuren, Frank & Panhuyzen-Goedkoop, Nicole & Solberg, Erik & Halle, Martin & La Gerche, Andre & Papadakis, Michael & Sharma, Sanjay & Pelliccia, Antonio. (2018). Recommendations for participation in competitive sports of athletes with arterial hypertension: a position statement from the sportscardiology section of the European Association of Preventive Cardiology (EAPC). European heart journal. 39. 10.1093/eurheartj/ehy511.
[12] https://www.hartwijzer.nl/kamers-en-boezems; https://www.hartstichting.nl/hart-en-vaatziekten/bouw-en-werking-hart. Consulted July 5th, 2022
[13] same
[14] same
[15] https://www.voedingscentrum.nl/encyclopedie/kalium.aspx. Consulted July 5th, 2022
