Before you get too excited about it let me clarify that generally health club dues are not deductible on your tax return.
"However, fees paid to health institutes may be deductible as medical expense only when such treatments by such institutes are prescribed by a physician and are substantiated by a statement by the physician that the treatments are necessary for the alleviation of a physical or mental defect or illness of the individual receiving the treatments"
The above is verbatim from Revenue Ruling 55-261 by Internal Revenue Service (IRS) which explains certain conditions when you can deduct your fees paid to health clubs as medical expense on your tax return.