Salma Hayek, 57, on workout regime that burns 1,000 calories as she shares age-defying snaps

Salma looked gorgeous in her green bikini and received countless compliments from fans on her svelte figure.

One Instagram user said she "gets more gorgeous by the day". Another commented: "You age like the absolute finest wine."

To achieve her age-defying beauty, the 57-year-old revealed the unusual skin care routine she follows to look decades younger.

As for her toned physique, Salma's former personal trainer Sara Shears revealed that she goes for cardio workouts, high-intensity interval training and a little strength training.

Cardio (anything that raises a person's heart rate) has many benefits. Regular cardio is effective for weight management, blood sugar regulation and lowering blood pressure.

HIIT is renowned for burning calories. It also improves stamina and strength and works to raise a person's metabolic rate so they can burn calories even after their workout is over.

For maximum muscular strength, slimmers should also incorporate strength training into their fitness regimes. This also boosts metabolic rate and is a great calorie burner.

An excellent form of cardio is swimming, which can be transformative. It's also an exercise Salma seems to really enjoy. Swim Now said: "Swimming has long been known as an excellent form of exercise and a fantastic way to stay in shape.

"Not only does it engage your arms and legs, but it also requires working your core."

The whole-body cardio workout may actually be more calorie-burning than other common fitness activities.

"Swimming enthusiasts will be pleased to hear that you can burn quite a lot of calories through swimming compared to many other forms of exercise, including the likes of walking, power walking, jogging and even dancing," said the experts at Swim Now.

"When you are walking or running, this is relatively easy because you only have to push through air, whereas when you are swimming, you have to push yourself through water, which has more weight and requires greater force to push through."

The amount of calories a person can burn when exercising depends on several factors.

Your body weight, muscle mass, gender, age, fitness level and training intensity can all make a difference.

However, the experts revealed the approximate number of calories burned by someone with an average build, putting in average effort over an hour.

Average calories burned through swimming per hour

• Front crawl: 976 calories
• Backstroke: 500 calories
• Breaststroke: 400 calories
• Freestyle swimming (choosing different swim strokes at random): 540-750 calories
• Aqua aerobics: 400-500 calories

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Water enthusiast Salma has shared several snaps of her swimming on Instagram, suggesting that this is an activity she partakes in regularly.

For World Ocean Day, she shared a video of her enjoying the sea. A scientific review in the International Journal of Circumpolar Health suggested that taking a dip in cold water may cut "bad" body fat in men and reduce the risk of diabetes.

Beyond Swim advised: "Swimming in open water can burn more calories than in the pool, as the lower temperatures will cause you to create heat energy by shivering. However, there’s not much point in swimming in open water for weight loss if you’re too cold to swim for long enough. Be sure to acclimatise slowly into colder water."

The National Water Safety Forum has essential information on staying safe when open water swimming.