The numbers suggest we are ticking health time bombs. At 45, we seem in rude health, even though most of us are overweight. Very few New Zealanders need medication to combat the effects of a misspent youth - bad food, alcohol, smoking and lack of exercise.
But our bodies can take the punishment for only so long. This week a joint study by Auckland, Waikato and Wellington councils estimated the cost of physical inactivity at $648 million a year. Just how quickly things go pear-shaped is highlighted in the 2012 New Zealand Health Survey, a "self-report" card on our collective body of health undertaken every five years.
The findings from interviews with 12,000 people suggest a positive prognosis when viewed alongside other health data. We are living longer. Death rates from major killers - heart disease and the various cancers - have fallen dramatically since the 1970s. But drill down into the survey and it's clear that, for all the advances in medical knowledge and treatments, many of us make life difficult for ourselves.
In our mid-40s, fewer than 5 per cent of New Zealanders need prescription drugs for high blood pressure or raised cholesterol.
By 55, nearly a third are on medication for high blood pressure and one in five is taking cholesterol pills.
Ten years on, nearly half are taking blood pressure medicine and more than 30 per cent are on cholesterol medication.
By age 75, one in four men will have had a heart attack or been diagnosed with angina (signifying heart disease) - a rate far higher than for women.
Diabetes rates follow a similar trend - doubling roughly every 10 years from 2.9 per cent of the 45-year-old population to 14.4 per cent of those aged 75, again higher for men than for women. Diabetes adds to the risk of heart disease.
What happens to us in middle age? It's not that we suddenly "go to the dogs", says Professor Rod Jackson of Auckland University's School of Population Health, who studies the causes and effects of disease as an epidemiologist.
Jackson says the sharp increase in prescription use from about age 45 reflects our bodies' response to an accumulation of abuse. Though it may look like a failure of health promotion efforts, Jackson says it's no bad thing that so many are popping pills in their 50s and 60s. It reflects earlier screening, drug advances and recognition that the new drugs can be used preventively to reduce heart attack risk, he says.
"The statistics look bad but actually we are doing incredibly well. Heart disease and stroke rates are plummeting and we are gaining in life expectancy. We are smoking less. Blood pressure and blood lipids are coming down.
"There are people who argue with medicalised health and there's some truth in that.
"[But] we do recommend a lot of people in their 60s and 70s take these drugs because they have accumulated a level of risk over their lifetimes. It doesn't mean they are about to die."
The survey doesn't look at the various cancers, which collectively remain our biggest killer despite the success of anti-smoking initiatives. Though death rates from lung cancer have halved since the 1970s, thousands each year need treatment for other lifestyle-linked cancers such as bowel (red meat, alcohol, weight gain) and stomach (salt and sugar).
For Government drug-buying agency Pharmac, it adds up to a major funding headache: about $200 million a year on blood pressure and cholesterol medication; another $60 million on diabetes monitoring and treatment; $130 million on cancer treatments.
It also suggests that significant numbers are not heeding the persistent messages about diet, smoking and exercise and are destined to spend at least a third of their - admittedly longer - lives on medication.
The survey shows New Zealanders have made little progress in the last five years in embracing healthier diets and lifestyles.
The number of women meeting the guideline of at least three servings of vegetables and two of fruit a day has fallen - from 51 to 48.9 per cent. Men's fruit and vege intake is improving, but they remain well behind women with just 37 per cent meeting the target. Pacific men are particularly averse to their greens and fruit - just 26 per cent getting the recommended amount.
Heart Foundation medical director Norman Sharpe agrees that having high numbers on heart medication is reducing heart attacks.
"The concern is whether it's the right people and whether it's doing what's intended because having them on medication is not sufficient. We need to ensure the blood pressure is more controlled.
"The bad news is that we see a potential new wave of coronary diseases in relatively young people, particularly in disadvantaged groups."
Sharpe says the predicted increase will stem from the epidemic in obesity and diabetes. A big focus on prevention and lifestyle change - both diet and exercise - is needed.
"All these things we keep hearing about but we need to do better."
Jackson says health promotion efforts sometimes attract flak for confusing people, but the messages have been fairly consistent for 30 years: don't smoke, reduce salt, alcohol and saturated fat intakes, exercise more.
"The only thing we haven't worked out is how to eat less. That's almost the last bastion of nutrition we've yet to find a solution for - how to get people to eat fewer calories."
Prominent GP Lannes Johnson says a key problem is that people are not receptive to health messages early enough.
"When you are 15, 25, even 35, you are invincible," says Johnson, of Harbour Health on Auckland's North Shore. "Then, in your 40s, your GP says you have to change. It's just a shame young people won't really listen. They don't visit the doctor very often so [GPs] can't get the message across.
"We would always try lifestyle modifications first but some patients either won't change - or it's already too late."
Johnson says the high numbers on preventive drugs is preferable to 20 years ago, when the first most men knew of their risk level was when they had a heart attack.
He concedes we could do better to avoid the need for medication through better diets and exercise. But he says a proportion of the problem is pre-ordained - through the genes we inherit - while socio-economic factors add to the difficulties facing many who want to change. These include a more sedentary workforce and the rise of processed and fast foods with their advertising budgets and resistance to healthy food labelling. He says patients generally are much more conscious of eating the right foods, while food manufacturers are becoming more responsive to reducing salt and saturated fat content.
Johnson wishes more could be done in schools to educate children about health and nutrition but says responsibility ultimately lies with parents. "But it's very hard for people on fixed budgets - I think about 30 per cent of New Zealanders are in that situation where every dollar counts."
With both parents working in many families, he says many find it easier and cheaper to eat takeaways than prepare a healthy meal.
Campaigns to combat smoking are throwing up similar disparities. While the daily smoking rate has fallen in five years from 18 to 17 per cent, rates for Maori, Pacific and Asian adults have not changed - and remain stubbornly high for Maori women, at 44 per cent.
Dr Marewa Glover, director of Auckland University's Centre for Tobacco Control Research, says it's not that these groups lack desire to quit but they need targeted support. Many hardcore smokers have co-dependency issues, including alcohol, she says. Ethnic minorities are concentrated in lower socio-economic groups and avoid going to the doctor until symptoms develop - they are not accessing preventive medicines early enough.
"I don't believe the health promotion campaigns are reaching into our lower socio-economic groups as well as they reach others."
Glover says quit-smoking and other health promotion campaigns need to be long-term, backed by support and take account of cultural differences. For instance, Pacific peoples' beliefs around beauty and body image are a challenge for obesity campaigns.
"There's a lot of mass media stuff that isn't effective. We have to get that level of analysis across populations and across the country."
One thing we don't have to worry about is hypochondria, the survey reveals, with 89 per cent of us reporting we are in good health, a figure that declines only slightly in old age.By Geoff Cumming Email Geoff