More than 40 million Americans care for adults with disabilities and aging individuals, according to a new study that values the volunteer services these family members provide at a whopping $450 billion annually.

The report released this week from AARP finds that the number of family caregivers is on the rise and more is being demanded of them.

In 2009, 42.1 million family members provided nearly 20 hours per week in unpaid care. These individuals handle everything from arranging services to advocating for and transporting loved ones. They are also increasingly taking on the role of nurse, removing catheters, giving injections and handling other medical equipment, the report found.

“Most caregivers don’t think of what they’re doing as work,” said Susan Reinhard, senior vice president for public policy at AARP and one of the report authors. “They think of it as what families do for each other.”

But caregiving has consequences, leading to stress, depression, financial compromises and social isolation, the report indicates.

“A key theme to emerge from systematic reviews of family caregiving studies over the past 30 years is that family care can have negative effects on the caregivers’ own financial situation, retirement security, physical and emotional health, social networks, careers and ability to keep their loved one at home,” the authors write.

While the AARP study factored in many who provide care for aging parents and other family members without developmental disabilities, the findings are yet another confirmation of the pressures faced by caregivers.

Just last month, a survey conducted by The Arc that looked specifically at families caring for people with lifelong disabilities found similar results.

In that study, caregivers reported feeling stretched financially and emotionally, with 1 in 5 indicating that a family member quit their job due to caregiving responsibilities and the majority saying that they felt tired or stressed some or most of the time.