Winter holidays—do they fill you with joy or with worries about gift-giving and family gatherings? Do summer vacations leave you relaxed or fretful over travel and money? If you’re feeling stressed out over supposedly fun things, it might be time to reassess. Take a few moments to learn how stress affects your health and what you can do about it.

Everyone feels stressed from time to time. Stress can give you a rush of energy when it’s needed most—for instance, competing in sports, working on an important project, or facing a dangerous situation. The hormones and other chemicals released when under stress prepare you for action. You breathe faster, your heartbeat quickens, blood sugar rises to give you energy, and your brain uses more oxygen as it shifts into high alert.

But if stress lasts a long time—a condition known as chronic stress—those “high-alert” changes become harmful rather than helpful. “Stress clearly promotes higher levels of inflammation, which is thought to contribute to many diseases of aging. Inflammation has been linked to cardiovascular disease, diabetes, arthritis, frailty, and functional decline,” says Dr. Janice Kiecolt-Glaser, a leading stress researcher at Ohio State University. She and other researchers have found that stress affects the body’s immune system, which then weakens your response to vaccines and impairs wound healing.

Research has linked chronic stress to digestive disorders, urinary problems, headaches, sleep difficulties, depression, and anxiety.

“Some studies have found the physical, emotional, and social effects of a disease like cancer to be stressful for patients, caregivers, and long-term cancer survivors,” says NIH’s Dr. Paige Green McDonald, an expert on stress and cancer biology. “However, there’s no definitive evidence that stress causes cancer or is associated with how long one survives after a cancer diagnosis.”

The top causes of stress in the U.S. are money and work-related pressures, according to a 2013 survey from the American Psychological Association. Stress can also arise from major life changes, such as the death of a loved one, divorce, illness, or losing a job. Traumatic stress is brought on by an extreme event such as a major accident, exposure to violence, or a natural disaster such as a hurricane or flood.

Caring for a person with severe illness—such as dementia or cancer—can also be a significant source of stress. More than a decade ago, studies by Kiecolt-Glaser and others showed that the stressful demands placed on caregivers can lead to poorer health, lower responses to vaccines, increased inflammation, and a more than 60% higher death rate compared to non-caregivers.

It’s not clear why some people can sidestep or recover more quickly from stress than others. These resilient people seem to “bounce back” more easily after stressful situations. Recent studies of animals suggest that resiliency may depend at least in part on our genes. But learning healthy ways to cope with stress can also boost your resilience.

“There are many different ways to cope with stress. We know from a lot of different studies that having close personal relationships—people with whom you can talk, with whom you can share your feelings—can be helpful,” says Kiecolt-Glaser. “So spending time with family and friends in order to maintain those relationships is perhaps one of the most crucial things you can do as a stress reducer.”

Unfortunately, Kiecolt-Glaser adds, “when we’re stressed, we tend to do the worst things that are not at all helpful to our health.”

For instance, stressed out people may tend to isolate themselves and not seek social support. “Exercise is a great stress reducer. But when people are stressed, exercise becomes less common and less appealing,” Kiecolt-Glaser says. “Instead of maintaining a healthy diet—also important to reducing stress—some people who are stressed tend to eat more donuts than vegetables.”

You may think that the agitation brought on by stress might help to burn calories. But evidence hints that the opposite is more likely. Kiecolt-Glaser and colleagues found that, compared to nonstressed people, those who were stressed burned fewer calories after high-fat meals and they produced more of the hormone insulin, which enhances fat storage. “So stress may contribute to weight gain and obesity through these biological routes,” Kiecolt-Glaser adds.

Getting enough sleep is also key to resilience and stress relief—although stress itself can interfere with sleep. To improve your sleep habits, go to bed the same time each night and get up the same time each morning, and limit the use of light-emitting electronics like computers and smartphones before bed. The light can reduce production of a natural sleep hormone called melatonin, which then makes it hard to fall asleep.

Beyond recommendations for exercise, healthy diet, social contacts, and getting enough sleep, Green McDonald says, “studies have also shown that mindfulness (focused attention on one’s own emotions) and other meditative practices can effectively relieve stress.”

“Mindfulness means staying aware and conscious of your experiences. No matter what we’re doing, we can always make time to bring our attention to our breath and body and stay there for a short period of time,” says NIH psychologist Dr. Rezvan Ameli, who specializes in mindfulness practice. “Recent studies show that even short periods of mindful attention can have a positive impact on health and well-being.”

Other NIH-funded studies have shown that mindfulness meditation can reduce stress, alter brain structure and function, and have a positive effect on the immune system.

“Mindfulness is a simple and effective tool that anybody can use to reduce stress,” Ameli says. Although the concept is simple, becoming more mindful requires commitment and practice. You can learn more about mindfulness meditation from local resources like yoga or meditation classes, mindfulness-based stress-reduction programs, or books.

If you feel overwhelmed by stress, talk with a health care provider or mental health professional. Medications or other therapies might help you cope. In the long run, reducing stress may help you to slow down and enjoy your time with the people and activities you really care about.