If Canadians are finding it easier to fight off the sniffles lately, feeling lighter in their step, or sleeping like a dream, a batch of new science has proposed a possible explanation: Good deeds are good medicine.
In the past three weeks, Canadians have performed more than their share of generous acts for strangers, from assisting the presidential election in Ukraine, to donating their time and money -- more than $147-million -- to victims of the tsunamis in Asia.
Overdosing on altruism may have a hidden perk.
Beyond changing the lives of those being helped, researchers propose it keeps Good Samaritans happier, healthier and living longer.
Researchers call it the "helper's high," the same kind of endorphin rush that runners get loping along a trail. A growing number of studies suggest this high can give the immune system a boost, speed recovery from surgery and cut down on those restless nights.
The science suggests that the old saying, "It's better to give than to receive," is literally true, said Jeffrey Schloss, an evolutionary biologist at Westmount College in California. "It's not just a moral cliché."
After decades of looking at what ails human nature, science is just starting to explore the influence of positive behaviour on health.
Using brain scans, scientists have found evidence that human beings are "hard-wired" to help each other.
Experiments show that thinking about someone else's problems lights up the same part of the brain that gets activated when we reflect on our own, while compassion registers in the brain's pleasure zones.
Good deeds make us feel more secure in our communities and reduce stress -- two keys to the health benefits of philanthropy, said psychiatrist Greg Fricchione, who studied altruism at Massachusetts General Hospital. "We are born to find social solutions for our problems," Dr. Fricchione said.
A Florida study of AIDS patients found that those who reported higher levels of altruism, including helping people with more advanced stages of the disease, were more likely to live longer.
Another study reported that within support groups, the people who were offering help, rather than always accepting it from someone else, fared better with their illness.
In a recent British poll of volunteers, half of those surveyed said their health had improved over the course of volunteering. One in five even claimed it helped them lose weight.
Experiments have also suggested that helping others changes our physiology.
When researchers sampled the saliva of Harvard students watching a videotape of Mother Theresa, they found evidence of temporary spikes in immunity-boosting chemicals. Women considered good neighbours in their community have been found to have higher levels of oxytocin, a hormone linked to a feeling of well-being -- although scientists have not established which comes first, the feel-good hormone, or the good deeds.
Science still has not settled the cause-and-effect quandary: It may be that happier, more resilient (and therefore healthier) people are the ones who volunteer in the first place, although researchers claim they see results accounting for differences such as personality.
But improving your health doesn't appear to be as easy as hauling out your chequebook for charity.
Stephen Post, director of the Institute for Research On Unlimited Love, which financed a scientific study of altruism, points out that how long the pick-me-up lasts depends on the extent and nature of the good deeds.
Performing them for good press only is believed to slash the health payoff. It's better to organize a garage sale for tsunami victims or field telephone calls for the Red Cross than simply to send in your cash.
And in the same way that it pays to eat broccoli several times a week, research suggests you'll be healthier offering up regular servings of compassion; one study even puts a number on it -- after tracking the moods and activities of subjects, it proposes that five acts of altruism a week is what it takes to substantially increase happiness.
The trouble is that our giving spirit tends to surface in spurts -- for one thing, all those acts of kindness can be exhausting.
Dr. Post points to a study of volunteers after the Sept. 11, 2001, terrorist attacks that found that only 25 per cent of them continued to make volunteering a significant part of their lives.
Stephanie Preston, who studies empathy at the University of Iowa, suggests the burnout factor explains why people react more generously to an acute problem than a chronic one -- for instance, tsunami aid versus the AIDS pandemic in Africa.
"With the tsunami, you could help in a pulse and move on with your life, and feel your guilt assuaged," Dr. Preston said.
She added that the victims in Asia had another edge: People find it easier to feel empathy when they can relate to the other person. North Americans could imagine themselves sunning on a beach holiday when disaster strikes.
However science unravels the health perks of good deeds, Dr. Post said it's clear that giving is an important "coping mechanism" in the face of disaster. Aside from the aid that results, he said, "It's very reassuring for the actual giver."