The stairs. They've been around for thousands of years, but their popularity took a serious hit with the invention of the lift.
But stairs are back! Move over triathlons and ironmans: racing up hundreds of steps in a skyscraper is the new ultimate fitness test.
There is mounting evidence to suggest that stair climbing, regardless of your pace, is one of the most effective and cheapest routes to fitness around.
Intense and powerful, it's a complete training package for heart, lungs, bones, muscles and flexibility, that can easily be added into everyday life.
The Government officially classes walking up stairs as "vigorous exercise", alongside running, tennis and football.
Research suggests that vigorous exercise can provide health benefits over and above that of moderate-intensity activities such as walking.
Vigorous exercise reduces the risk of many illnesses, including cardiovascular disease, diabetes, osteoporosis and some cancers.
Many athletes incorporate stair climbing into their training regime to help them develop their lung capacity and lower body power.
Because of the steepness, physiotherapist Nick Sinfield says that walking up stairs is, arguably, more challenging than walking up a hill.
Working your muscles in this way will improve your overall fitness and can also improve your performance in other sports, such as running.
"Stair climbing can help to improve your lung capacity and muscle efficiency, meaning you can run faster for longer," says Sinfield, of back experts Spring Active.
Stair climbing also works the stabilising muscles around the hip, which help to prevent injury.
Every little helps
Walking up the stairs burns more calories per minute than jogging (although you're unlikely to go for a 30-minute stair climb).
However, every little helps, and if you’re looking for an easy way to add more activity into your day, taking the stairs is a great option.
The average person burns roughly one calorie for every 10 steps up and one calorie for every 20 steps down.
One of the best things about stair climbing is that it's easy to build it into daily life and counts towards your recommended 150 minutes of weekly exercise.
By making a habit of using the stairs instead of lifts and escalators, you can, through small increments, make a significant difference to your health over time.
Obesity expert Dr Louisa Ells says: “Stair climbing is a great way of seamlessly building more physical activity into your everyday life."
You can measure precisely how good taking the stairs is for you with a free web and app-based health initiative called StepJockey.
StepJockey allows you to track how many calories you’ve burned taking the stairs, set personal goals and share with friends.
You can use their website to print signs showing how many calories you can burn walking up a specific set of stairs, anywhere in the world.
In buildings equipped with StepJockey signs, stair climbing increased by up to 29% in trials involving more than 250,000 stair/lift journeys.
Holly, 24, burned an extra 195 calories a day, to shape up for her wedding, by using the stairs at work and on her daily commute on the London Underground.
She climbed up and down the 100 steps to her fifth floor desk three times a day and 814 steps on her journey to and from work.
“I was getting married and I really wanted to lose some weight and tone up for my big day,” says the marketing assistant.
“Stair climbing proved to be an easy exercise to lose weight. It fitted in with my day, didn’t feel like exercise and I didn’t feel at all self-conscious.”
If tracking your calorie burn isn’t sufficient motivation, StepJockey has developed several workplace challenges to encourage staff to take the stairs.
These include "Climb Everest", "Burn a Million" (calories) and "Seven summits", and can be entered as a team or an individual.
The Department of Health-funded initiative gets the big thumbs up from long time walking advocate Sir Muir Gray, Chief Knowledge Officer to the NHS.
"Every building should promote its stairs, and StepJockey can help with that," he says.
"Climbing up stairs builds stronger leg muscles, joints and hearts. I say down with lifts, up with stairs."