Nicole Scherzinger says jogging is the form of exercise she relies on to keep fit.
After years of trying different workouts, the 'Don't Hold Your Breath' singer has discovered running works best for her and when she is pounding the streets or treadmill she often gets her best ideas.
Speaking to Now magazine, she said: "As for exercise, jogging is a great cardio workout but also helps me get in the right frame of mind. I get creative ideas and I'm very productive when I'm running. I love spin classes and yoga, too."
Nicole says the CrossFit workout got her in shape very quickly but she found the programme - which involves elements of Olympic weightlifting and gymnastics as well as other sports and exercises - just too hard for her.
The 'Cats' star - who recently split from Lewis Hamilton - said: "I tried CrossFit once. It got me in shape really fast but it was so intense - too much. Hiking and running in the canyons in LA is really effective but it's not my favourite - it's hardcore! Boxing wears me out too. I'm tired after three minutes."
Nicole, 36, spends less time in the gym now than she did in her 20s but believes the hard work she put in previously has given her good muscle memory.
She said: "I actually work out less often now. When I was younger I worked out like a fiend, so maybe that's helped me. It's carried me in good stead for my 30s. I'm proud of myself if I train four times a week. If I'm really getting in shape for something it's five to six days a week."