Canadians over 40 prefer to have sex after dark. (Shutterstock)

Canadians over 40 prefer to have sex when the sun is down, according to a new survey.

The survey -- commissioned by erectile-dysfuction drugmaker Eli Lilly Canada -- found that 60% of respondents said they prefer to have sex at night.

About 27% said they prefer the morning and 13% prefer the afternoon. Quebecers are most likely to have sex in the morning -- at 36%. Those living in the Prairies -- 18% -- are the least likely. Despite the nighttime preference in the over-40 crowd, 40% of the respondents said being tired is their No. 1 barrier to having sex at their preferred time.

About 25% said work is their main obstacle, 18% said an inability to find private time with their partner and 17% cited medical issues.

Most respondents (60%) said they want a spontaneous sex life, but only 44% said they have one.

"Erectile difficulties and other life circumstances can get in the way of couples having relaxed and carefree sex whenever and wherever they want," said Anna Toth, a registered marriage therapist in Ontario. But 61% of respondents said their sex life has gotten better with age.

The online survey questioned 1,000 people aged 40 and over in April.