Fend off the flu by making pretzels: practising yoga can strengthen your immune system, say 
scientists in Japan. After 
a 90-minute yoga session, people had nearly double their usual concentration of salivary beta-defensin 2, a peptide that attacks microbes. Study author 
Dr Nobuhiko Eda, says 
the relaxation provided by yoga probably lowers 
production of the hormone cortisol, which then 
triggers the release of beta-defensin 2. And a separate study from India found that even 35 
minutes of yoga a day 
can curb spikes in cortisol. 
Try some of these yoga poses.