NEW YORK (Bloomberg) — Employees younger than 44 have less tolerance than their older counterparts for workweeks that reach 60 hours and beyond, a study found. The dislike among women was even more prevalent.From 30 to 36 percent of the younger employees holding those high-pressure "extreme jobs" expected to leave in the next two years, the study found. That compares with 19 percent of older workers, according to the study, published in the December issue of the Harvard Business Review.

Sixty-five percent of those surveyed across all age groups would decline a promotion if it were more demanding of their energy. The findings suggest that companies will have difficulty filling top positions when the older generation retires, the authors said.

"The ultimate price may be paid in succession planning if maxed-out professionals stop striving for top jobs," the authors, Sylvia Ann Hewlett and Carolyn Buck Luce, wrote.

"A clear majority" of the women — 57 percent — said that they don't want to continue at such an extreme pace for more than a year. Less than half, or 48 percent, of men expressed the same sentiment.

Women in the US were less likely to work long hours, perhaps because "they seem particularly tuned into — and pained by — the fallout on their children".