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Physical fitness is good for the heart, brain and overall health. But a specific type called cardiorespiratory fitness may help predict the odds of having a heart attack, especially for women, new research shows.

Higher cardiorespiratory fitness translated to lower heart attack risk, with women appearing to benefit the most. The findings suggest “cardiorespiratory fitness can be used as a risk calculator for first heart attacks,” said Rajesh Shigdel, lead author of the Norwegian study published Wednesday in the Journal of the American Heart Association.

Length and intensity of physical activity

“Measuring cardiorespiratory fitness will tell you which risk group you are in,” said Shigdel, a researcher in the Department of Public Health and Nursing at Norwegian University of Science and Technology in Trondheim, Norway.

Cardiorespiratory fitness reflects the body’s ability to transport oxygen during sustained physical activity. It can be measured using VO2 max, the maximum amount of oxygen the body can use during exercise. A higher VO2 max indicates higher cardiorespiratory fitness.

Relying on data from one of the largest health studies ever performed, Shigdel and his team estimated cardiorespiratory fitness for more than 26 000 Norwegians who were 56 years old on average and free of heart disease when the study began. Researchers tracked their health for up to 15 years.

Because VO2 max scores were not available for all participants, researchers estimated cardiorespiratory fitness based on the length and intensity of physical activity each week. Among women, those with high levels of cardiorespiratory fitness were 25% less likely to have a first heart attack than those with low levels, whereas men with high levels of fitness were 10% less likely to suffer a heart attack than those in the low fitness group.

People who want to increase cardiorespiratory fitness should strive to be physically active at least 150 minutes each week and minimise time spent being sedentary, Shigdel said.

But that doesn’t have to mean spending hours at the gym each day. “Those who are somewhat active will still have some benefit,” he said. “It’s better to have something than nothing.”

Heart attacks are not always fatal

It’s unclear why exercise affects men and women differently, said Dr Aaron L. Baggish, director of the Cardiovascular Performance Program at Massachusetts General Hospital in Boston. But he cautioned against placing too much weight on the finding that women reaped a greater protective benefit than men.

“The take-home message for this study should not be that fitness doesn’t matter for men,” said Baggish, who wrote an editorial accompanying the study. “The message should be that the fitter you are, the less likely you are to have your first heart attack.”

Previous studies have consistently shown higher levels of cardiorespiratory fitness are associated with fewer heart problems. However, most prior studies either haven’t included women or didn’t report findings by gender, said Shigdel, despite the fact that heart disease behaves differently in women versus men. For example, women ages 45 and older are more likely to die within a year of a first heart attack than men of the same age.

Most research also has looked only at whether fitness was related to a higher risk of death from cardiovascular disease, rather than a first heart attack – an important distinction because heart attacks are not always fatal. “Our results are better suited for assessing disease risk,” the authors noted.

In terms of cardiovascular risk, Baggish warned against focusing on physical fitness at the exclusion of other factors. It is equally important, he said, to quit smoking, eat a diet rich in fruits and vegetables, stay away from processed foods and avoid stress.

“If you have high blood pressure, high cholesterol and other risk factors, you can’t exercise yourself out of trouble,” he said. “Nobody can exercise enough to get complete immunity from heart disease.”

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Have you started feeling like your allergies are acting up earlier every year, or maybe they’re lasting longer?

New research suggests it’s not just your imagination – climate change appears to be disrupting nature’s usual calendar. Areas with an earlier spring had a 14% higher rate of seasonal allergies (hay fever), the researchers found.

High-resolution satellite data

“Climate change is real. It’s impacting our ecosystem now, and that, in turn, is impacting our health,” said study author Amir Sapkota. He’s an associate professor at the Maryland Institute for Applied Environmental Health in College Park, Maryland.

For the study, the investigators used high-resolution satellite data provided by NASA to identify the start of spring throughout the United States. They linked this information to data from a nationally representative sample of Americans collected by the US Centers for Disease Control and Prevention.

Sapkota said the researchers looked at what happened if spring began earlier or later than normal.

“When spring starts early, the burden of allergic disease – or hay fever – goes up. But we also saw high hay fever prevalence when spring was late, too. It’s like mortality with extreme temperatures. Temperatures that are very hot or very cold can kill us. There’s a sweet spot that’s OK,” Sapkota explained.

If the season starts early, trees bloom and release pollen earlier than usual and may release pollen for a longer time. “This is not a good thing if you’re suffering from allergies,” he said.

Changes aren’t uniform

Sapkota said the findings for increased problems if spring was delayed were a surprise. He doesn’t know exactly why the late spring would make allergies worse, but suspects it may be because everything then blooms at once – trees, flowers, grasses.

“All of a sudden, things go gangbusters at one time. The season may end up shorter, but you’re bombarded by it,” he said.

Dr John Balbus, senior advisor for public health at the US National Institute of Environmental Health Sciences, reviewed the study.

He said, “This is the first confirmation from health data that changes in the length and timing of spring could lead to a higher prevalence of allergy symptoms.”

Balbus said the changes in spring’s timing aren’t uniform across the United States. “There’s a trend over time to earlier pollen seasons as you go up to more Northern latitudes attributable to climate change. It’s up to a few weeks earlier by the Canadian border, but not so much in Texas,” he noted.

More medication may be necessary

But an earlier spring isn’t always the case. “What we are seeing in a lot of meteorological data is a trend to increasing variability,” Balbus said. For example, the East Coast had a colder winter due to a drop in the polar vortex, which may delay the blooming season.

So what does all this mean for allergy sufferers?

Allergist Dr Punita Ponda from Northwell Health in Great Neck, New York, said, “For most allergy sufferers, the old dogma of starting preventive medications in mid-March or so is not going to be enough.”

She said people with spring allergies will have to start paying attention to pollen counts in April and may need to start taking their allergy prevention drugs in late February if pollen counts start spiking. And, she said, they may need to continue taking these medications until at least mid-June.

“They may need to take medications for longer. And for brief periods of time, more medication may be necessary,” she said. She advised people to contact their doctor for specific instructions based on their situation.

The report was published online recently in the journal PLoS ONE.

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