Kylie Jenner works out twice a day. Here's why trainers say once a day is enough to meet your goals.

• Kylie Jenner recently shared on social media that she's working out twice a day.
• Personal trainers say that for most people, consistency is better than spending hours in the gym.
• Too much exercise can also backfire for weight loss and muscle gain.

Last week, Kylie Jenner revealed on Instagram that she's been logging two workouts a day. The celebrity showed followers a clip of herself on a treadmill around midday, after a previous 7 AM sweat session.

Social posts suggest Jenner maintains her figure by keeping up with this intense exercise schedule.

However, experts say that for a majority of casual gymgoers, working out twice a day is more likely to lead to burnout and injury than results. You also probably don't need to work out twice a day to meet your fitness goals. Here's what personal trainers recommend instead.

Three to five workouts a week is ideal for most people

To get results in the gym, it's quality and consistency of workouts that matter most, personal trainer Irving "Zeus" Hyppolite previously told Insider.

"People start to do too much. You want to maximize your time and try not to drown in the gym for hours," he said.

If you aren't currently exercising, start by scheduling a few workout days a week and sticking with it until it becomes a habit, he recommends. If you already work out, add an extra day or two to your existing routine.

But there's a limit to how much your body can accomplish in any given time. A good benchmark is three to five days a week, for 45 minutes to an hour each day, including warm-up and cool down time, Hyppolite said.

Do more than that, and you'll end up putting in a lot of work for little to no additional benefit, he explained. Instead, it's better to get the most out of each workout day-to-day and week-to-week, and be patient as the results happen over time.

For weight loss or maintenance, adding an extra workout is even less helpful, personal trainer Bryan Goldberg previously told Insider.

"It's not very sexy to talk about, but it's really important that if you're losing body fat, you might need more rest than before," he said.

Competitive athletes might train two or more times a day, but they're not trying to lose weight, and they eat a lot more calories to fuel their bodies, including plenty of protein and carbohydrates.

Unless you're trying to compete in an elite sport, you're better off staying consistent with moderate amounts of exercise. Spending hours a day on multiple workouts won't help if you can't maintain that intensity over time, the experts said.

Too much exercise can backfire

Overdoing it on your fitness goals can even stall your progress, whether that's a crash diet or an over-the-top exercise regimen, according to Goldberg.

"It can be effective in the short term, but in the long term, it's more detrimental than helpful," Goldberg said.

That's because recovery is a key part of making progress in the gym, from building strength to reducing body fat. Without adequate rest, your body can't adapt and change in response to the work you've put in, Goldberg explained.

And every effort (including diets and workouts) puts additional stress on your body, which adds up over time, leading to injuries or exhaustion, burnout, and frustration.

"If it leaves you feeling drained, it's not worth the aesthetic changes," Goldberg said.