A growing middle class and consumers' evolving attitudes toward health and travel have fuelled a global spa and wellness industry worth an estimated $3.4 trillion in 2013, according to a new report.

Nutrition and weight loss, preventative and personalized health, complementary and alternative medicine, and beauty and anti-aging treatments were the biggest growing sectors, the report compiled by the non-profit research center SRI International showed.

"All across the world we have seen, from Asia to Europe to Africa to North America, more and more people are consciously thinking about healthy food, exercising, looking to nature, getting massages and doing yoga," said Ophelia Yeung, a senior consultant for SRI International who led the study.

Spa treatments and products, alternative and complementary treatments and weight-loss programs once considered beyond the means of many people, she added, are becoming more mainstream with a growing middle class.

While medical care treats illness and disease, wellness is focused on prevention through a variety of healthy habits, nutritional eating, exercise and treatments.

To compile the report researchers looked at wellness sectors ranging from mind and body fitness to beauty and anti-aging, spas and workplace wellness.

The global spa industry generated $94 billion last year, according to the Global Spa and Wellness Economy Monitor report, up from $60 billion in 2007.

With more than 32,000 spas, Europe had the highest revenue of $29.8 billion, followed by the Asia-Pacific region with $18.8 billion and North America with $18.3 billion.

Emerging markets in the Middle East and Africa have been growing the fastest in terms of adding spas. In Asia, China and India are leading growth, while in Europe it is Eastern Europe, Russia and the Baltic states.

Thermal/mineral springs generated $50 billion worldwide but the biggest industry sector was wellness tourism, or travel associated with maintaining or enhancing one's personal well-being and health, which accounted for $494 billion.

"Wellness travel is a very fast growing segment within travel. That's because as people become more conscious about a healthy lifestyle they naturally want to extend that when they travel," Yeung explained.

The report showed that the number of people taking international and domestic wellness tourism trips grew by 12 per cent from 2012 to 2013. That was 36 per cent faster than overall tourism trip growth, which is estimated at 9 per cent.

The SRI report was commissioned by the annual Global Spa & Wellness Summit. More than 400 wellness industry leaders from 45 countries attended the 2014 summit in Morocco earlier this month. – Reuters