Putting something on the line, usually money, can make you train more consistently while the stakes are active. In one randomized trial, people who stood to lose money for missing a step goal hit it on 45% of days, compared with 30% for a control group and 35% for people who could earn the same amount. The effect faded once the money stopped, though, so a workout bet works best as a short push through a busy stretch while you build a habit that lasts without it.
This guide covers what the research shows, the main tools, how to design a short challenge, and when to avoid stakes altogether.
What is loss aversion? #
Loss aversion is the tendency to feel a loss more strongly than a gain of the same size. Losing $20 stings more than finding $20 pleases. Behavioral economists have used that quirk to design incentives: instead of paying you for each workout, they give you the money up front and take some back every time you skip.
It suits exercise because the costs of training are immediate (time, effort, sweat) while the benefits arrive slowly. A stake you’d lose today balances that out.
Do workout bets actually work? #
The evidence says yes while the stakes last, with some hope for longer effects in people who choose to commit.
| Study | What they did | What happened |
|---|---|---|
| Patel et al., 2016, Annals of Internal Medicine | 281 adults aimed for 7,000 steps a day. One group got $1.40 for each successful day, one got a lottery, and one got $42 a month up front and lost $1.40 for each missed day | The loss group hit the goal on 45% of days, versus 30% for controls, 35% for the gain group and 36% for the lottery group. After the incentives ended, no group differed from control |
| Royer, Stehr and Sydnor, 2015, American Economic Journal: Applied Economics | Employees at a large company were paid to use the company gym for four weeks, and some were offered a commitment contract afterward | The paid incentive alone produced only small lasting effects. People who took up the commitment contract showed significant changes in gym use that were still detectable years later |
Two cautions. The lasting effect in the gym study came from people who chose to sign up, who may have been more motivated to begin with. And in the step trial, the benefit vanished when the incentive did. Plan for the handoff from the start.
Which tools let you bet on your workouts? #
| Tool | How it works | Cost |
|---|---|---|
| stickK | You write a commitment contract with a goal, a stake and an optional referee. Forfeited money goes to a friend, a charity, or an “anti-charity” you dislike | Free for individuals |
| Beeminder | You log data toward a goal, manually or through connected apps. Fall below your “bright red line” and it charges your card, and the pledge rises after each slip | Basic use is free, premium plans are optional |
| Group step and fitness games such as WayBetter | Groups join a challenge around steps or other goals, often with money involved | Varies. Check each game’s rules and fees before joining |
| A friend with your cash | You hand over $50 and get $10 back for each week you hit your target | Free, if your friend is honest |
stickK was founded in 2007 by Yale economists Dean Karlan and Ian Ayres. Beeminder connects to more than 40 services, including Fitbit and Apple Health, which saves manual logging for step and activity goals. Terms and fees change, so read each service’s current rules before you put money in.
How do you design a short loss-aversion challenge? #
- Pick a short window. Two to four weeks, ideally covering a crunch period like exams or a project deadline.
- Define the rule precisely. “Three sessions of at least 20 minutes a week, each logged the same day” is enforceable. “Work out more” isn’t.
- Choose a stake that stings but can’t hurt you. Enough that you’d rather train than lose it, never money you need for rent or food.
- Pick a referee. A friend or classmate who checks your log once a week.
- Write the sick-day rule in advance. For example, illness pauses the contract with a note from you to the referee. Without this, people train sick to save their money.
- Set the end date and what comes next. Decide now which habit system takes over when the stakes stop.
Five challenge templates you can copy #
| Template | How it works | Best for |
|---|---|---|
| Deposit refund | Give a friend $40. Earn back $10 for each week you hit your session target | People who respond to money |
| Anti-charity | Missed week sends $20 to a cause you’d hate to support | People whom a small amount won’t move |
| Social stake | Miss a session and you post an agreed, harmless forfeit in the group chat | Students and friend groups |
| Owned week | On Monday, tick every planned session as “yours.” Each skip crosses one out | People who like visible progress |
| Pre-bought treat | Buy a treat before the challenge. Fail and it goes to a friend | People who don’t want cash involved |
The “owned week” uses a related idea: people protect what they feel they already have. Starting the week with three sessions ticked, and losing one for each skip, feels different from starting at zero and earning them.
Using a workout bet during crunch time #
Exam season and deadline weeks are when routines collapse, and also when a short contract helps most. Keep the rules gentle:
- Stake attendance, not intensity. A 15-minute floor session should count. The goal is to keep the habit alive, not to set records.
- Lower the target. If you usually train four times a week, make the contract three.
- Keep it short. Two weeks around the exams or deadline, then stop.
Our guide to the five streak shields has more ways to keep training through busy weeks without any money involved.
When should you avoid workout bets? #
Skip money stakes, or talk to someone first, if:
- The money matters. A stake should never threaten bills or savings.
- You have a history of disordered eating or compulsive exercise. Penalties can feed the same all-or-nothing thinking. Speak with a health professional instead.
- The goal is scale weight. Bets on weight loss can push people toward crash diets and dehydration before weigh-ins. Stake behaviors like sessions, not body weight.
- You’d train injured to avoid losing. Build pain and illness exemptions into the rules, and use them.
What happens when the contract ends? #
Expect motivation to dip, because the trial evidence says it will. Bridge the gap before the stake expires: switch to a weekly streak with reward tiers, keep the same training slots, and keep logging. Our guide on how to stay motivated to work out walks through that eight-week plan, and how to gamify your fitness goals covers point systems that reward progress without money.
A clear log also keeps a contract honest, since your referee needs proof. One Gym Man records every session with its date, exercises, weights, reps and run distances, and the progress screen shows your total workouts and current streak, which is easy to screenshot for a weekly check-in. The app itself has no betting and no leaderboard. It rewards consistency in-game instead: consecutive training days raise a Morale stat that multiplies your damage against its monster ladder.
Frequently asked questions #
Do fitness bets actually work? #
They tend to work while the money is on the line. In a randomized trial, a loss-framed incentive raised the share of days people hit a step goal from 30% to 45%, but the effect disappeared after the incentive ended. Use a bet to get through a short stretch and build a habit alongside it.
How much money should I put on a workout bet? #
Enough that losing it would annoy you, and small enough that losing it wouldn’t cause real harm. For many people that’s somewhere between the cost of a meal out and a week of groceries. If you find yourself dreading the stake rather than the missed workout, lower it.
Is stickK free? #
stickK is free for individuals. You only lose money if you set a financial stake and miss your goal, and you choose where that money goes, such as a friend, a charity or an anti-charity.
What if I get sick during a commitment contract? #
Pause it. Write an illness rule into the contract before you start and tell your referee when you use it. Training while sick to protect your money defeats the purpose of getting healthier.