Kathryn Thomas has said she has not gone for an early morning or late evening run since the death of Ashling Murphy.
The Operation Transformation host was speaking as Thursday marks one year since the school teacher was killed while out for a run in Tullamore, Co Offaly.
Kathryn told The Hard Shoulder she would always exercise during daylight hours.
"The thing that was so shocking was that it was broad daylight," she said.
"We're constantly worried about getting out before it's dark, and it is more difficult because the evenings are shorter.
"I would always suggest at this time of the year - or for me personally - I would always try and get my walk or my run in when it's bright, which is difficult.
"That's where I feel safest at this time of the year."
Kathryn said she would feel safe running early in the morning, but her husband would not.
"I would, but certainly he would feel more comfortable - and now that we've had these conversations, I would never have really questioned it before," she said.
"Now, particularly in light of Ashling's case, put it this way: I've not gone early morning or late evening since then unless I'm with a group.
"That's why there's so many walking groups, there's so many running groups.
"Your local GAA club will have flood-lit pitches which is safe.
"There's a lot of people who live rurally with roads with no footpaths, so you've got that to contend with as well.
"It's about finding somewhere where you feel comfortable.
"If you're not comfortable, and you feel like you're checking yourself all the time, you're not going to enjoy it.
"Exercise shouldn't be about a chore, it should be about being enjoyed," she added.