From the May 2012 issue of Runner’s World
Medical tests you need to ace, because running does not grant you full immunity
By Kristin Pladson
Chances are you've memorised your personal bests, race pace, and maybe even target heart-rate. But do you have any clue what your blood pressure is? How about your blood-sugar level? “Many runners think that because they’re athletic, they won’t suffer from health problems like hypertension or diabetes,” says Mark Harrast, M.D., a sports physician at the University of Washington. But no matter how much you run, he says, you can’t change important risk factors like your genes, your family history, your ethnic background, or your age. Other aspects of your lifestyle count, too, including how you manage stress and your eating habits. The best way to safeguard your long-term health is to catch troublesome issues early. As you begin to plot your running goals, ask your doctor about adding the following screenings to your calendar.
There are no early symptoms of high BP (hypertension), but the longer it goes unnoticed – and untreated – the more damage occurs to your heart and blood vessels, upping your chances of a heart attack or stroke. Running does keep blood pressure in check, because exercise helps dilate the body’s blood vessels and enables blood to circulate more freely. Still, Dr Harrast warns against assuming you’re immune to hypertension. About one in four Australians and one in five New Zealanders are thought to have high BP. And with every birthday your risk goes up. Your favourite foods also play a role, with salt, saturated fats, and too much alcohol being top aggravators. Certain medicines can also raise BP.
For Joe Bowman, 48, stress and his gene pool were his primary risks. In early 2008, just a few months after completing his first marathon, the website developer was put on ACE inhibitors to control his blood pressure. “My doctor was happy with my diet and activity level. Medication was my only option.”
When to screen: “As people move into adulthood we urge them to know their numbers. Everyone over 35 and people who have other risk factors for heart disease, such as being overweight, smoking or a family history of heart disease should get their blood pressure checked every one to two years,” says Dr Robert Grenfell, Clinical Issues Director at the Heart Foundation (www.heartfoundation.org.au).
Your target: Blood pressure under 120/80 mmHg
Some cholesterol – a waxy, fatty substance – is necessary to build healthy cell membranes and protect nerve cells in your brain. But whatever the body doesn’t use to perform those vital jobs can cause harm. The “bad” form (LDL) clings to the arteries, sabotaging blood flow to your heart and triggering inflammation. The “good” form (HDL) soaks up and removes excess cholesterol.
Increasing good cholesterol is as beneficial as decreasing bad, say doctors. Lacing up is a great way to boost HDL. But because the precise reasons behind the sport’s positive impact aren’t fully understood, and no one knows the exact “dose” needed for maximum effect, even the fittest runners shouldn’t take healthy levels for granted. (After menopause, good levels go down and bad levels go up.)
When to screen: Your doctor will advise you on how often to get tested, depending on your risk factors, but the Heart Foundation recommends that people 45 and over get tested every one to two years. You should do the same if you’re under 45 but have risk factors such as being overweight, a family history of heart disease, having diabetes, being a smoker or if you are of Aboriginal or Torres Strait Islander descent.
Your target: Total cholesterol below 5mmol/L; LDL below 3mmol/L; HDL above 1mmol/L
An underactive or overactive thyroid can make your favourite workouts far more difficult. That’s because the thyroid hormone regulates how much energy reaches all cells, including muscle cells.
Too little TSH (hypothyroidism) can leave you feeling weak, while high levels of thyroid hormones (hyperthyroidism) speed up your heartbeat and can make you jittery. More disturbing, however, is that the estimated 200 million people in the world who have thyroid disorders also grapple with serious weight, sleep, depression, cholesterol and fertility problems. Running is one way to support healthy thyroid function (although overtraining can suppress TSH), but genetics are most often to blame when TSH levels are out of balance.
When to screen: The earlier the better. The Australian Thyroid Foundation (www.thyroidfoundation.com.au) recommends screening for women who are contemplating pregnancy, and people who have a family history of thyroid disorders or have thyroid disorder symptoms. People who fall under these categories should continue to screen regularly.
Your target: TSH level usually ranges between 0.5–4.0mIU/L, but Australian Thyroid Foundation Medical Advisors recommend being under 2.0 for healthy thyroid function.
IRON (SERUM FERRITIN)
Iron is the key ingredient to the production of haemoglobin, which ferries oxygen from the lungs to the muscles. If haemoglobin is low, your workouts may pay the price. (Runners already tend toward lower iron stores because of increased blood volume.) Yet there are no alarm bells that announce early iron deficiency. Symptoms – increased fatigue, lack of energy, muscle soreness, achy joints and sliding performance – match up to a number of things, including the flu or overtraining. But if iron stores aren’t returned to a healthy state, heart problems may arise.
When to screen: As symptoms occur; vegetarians and women may want to ask about preventive screenings.
Your target: Let your doctor explain your blood test result, says senior nutritionist at Nutrition Australia, Queensland, Aloysa Hourigan. “It is more complex than just being above a certain figure,” she says.
Generated by the carbohydrates you eat, blood sugar (a.k.a. glucose) is a major source of your body’s fuel. To use this fuel for energy, your body needs the hormone insulin to take sugar from the blood into the cells. With Type 2 diabetes (the most common form), the cells either ignore the insulin or the body doesn’t produce enough of it. Glucose then builds up, leading to problems with the heart, kidneys, eyes, nerves and blood vessels.
Running lowers blood-sugar levels as muscles burn glucose. But that doesn’t mean you should skip this test, especially if you have a family history of diabetes.
In its early stages, diabetes often goes unnoticed: you might feel thirstier and hungrier than usual, become tired and cranky, or have to make more trips to the bathroom. At least 721,000 people in Australia report that they have Type 2, and in New Zealand more than 170,000 people have it – but it is estimated that about one third of people with Type 2 don’t know they have it. Yet early detection helps many athletes with diabetes enjoy rigorous training and racing.
When to screen: Risk assessment should begin at age 40 (18 for Aboriginal and Torres Strait Islanders); periodic re-testing for undiagnosed Type 2 is recommended each year for people with impaired glucose tolerance or impaired fasting glucose, and every three years for all other people.
Your target: If your random or fasting blood-sugar level is below 5.5mmol/L, diabetes is unlikely. Above this, Diabetes Australia (www.diabetesaustralia.com.au) recommends an oral glucose tolerance test. Targets are different for people with diabetes – consult your doctor.
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