Norah O'Donnell and Her Trainer on Lifting Heavier as You Age

Norah O'Donnell devotes the latest episode of her CBS News series "Healthful" to exercise, framing it as what she calls an insurance policy for the future.

O'Donnell is joined by her personal trainer, the fitness expert Kira Stokes. The two have been working out together for 12 years. In that time, according to the episode, Stokes pushed O'Donnell to lift heavier weights — a change O'Donnell says she initially resisted.

O'Donnell says she has since come to understand what is at stake: people lose up to 8 percent of their muscle mass every decade after the age of 30. That figure is the starting point for much of the conversation, which turns to strength training as a long-term investment rather than a short-term fix.

The episode also takes up the emotional side of exercise. O'Donnell and Stokes discuss the connection between movement and mental health, a link that has drawn growing attention from fitness professionals and clinicians alike.

For viewers who are not exercising at all, the two address how to get started — the practical question that tends to stop beginners before they begin. They also weigh in on weighted vests, one of the more visible recent fitness trends, in which added load is carried during walks or workouts.

O'Donnell closes the episode on a lighter note, answering which exercises she likes most and which she likes least.

The series is inviting suggestions from its audience on what to cover next. Viewers can text O'Donnell at 202-217-1107 with topic ideas.

"Healthful" is presented as a conversational health and fitness program built around interviews, with O'Donnell — a longtime CBS News anchor and correspondent — talking with experts in each episode. This installment is the fourth.

The discussion does not amount to individual medical advice, and the episode's guidance is framed as general information from a trainer and her client rather than a prescription for any one viewer.