The Effect of Mixed Exercise and Metabolic Stress in Relationship to Age in Healthy Men

The Effect of Mixed Exercise and Metabolic Stress Upon Pituitary Secretion in Relationship to Age in Healthy Men: a Pilot Study

Aging in men reduces the amount of luteinizing hormone (LH) and testosterone (Te) secreted in each burst. Stress-associated mechanisms introduced by acute illness and chronic disease decrease LH and Te secretion further. A major unresolved issue is whether the aging process heightens the negative effects of a stressor (whether physical or metabolic) upon LH and Te secretion. This study will assess LH and Te secretion in response to a physical stressor (maximal exercise) and a common metabolic stressor (hyperglycemia) as a function of age in healthy men ages 18-80 yr.

Inclusion Criteria:

• Community dwelling, healthy men age 18 to 80
• Body-Mass Index (BMI) 18-30 kg/m2
• Willingness to provide written informed consent
• Physician acceptable screening ECG for participants 60 years and older

Exclusion Criteria:

• recent use of psychotropic or neuroactive drugs (within five biological half-live)
• obesity (outside weight range above)
• acute weight change (loss or gain of >2 kg in 6 weeks
• Laboratory test results not deemed physician acceptable
• triglycerides > 300
• BUN >30
• creatinine > 1.5 mg/dL
• liver functions tests twice upper limit of normal
• electrolyte abnormality
• anemia; hemoglobin < 12.0 gm/dL
• drug or alcohol abuse
• psychosis, depression, mania or severe anxiety
• acute or chronic organ-system disease
• endocrinopathy, other than primary thyroidal failure receiving replacement
• untreated osteoporosis
• nightshift work or recent transmeridian travel (exceeding 3 time zones within 7 days of admission)
• PSA > 4.0 ng/mL, History or suspicion of prostatic disease (elevated PSA,indeterminate nodule or mass, obstructive uropathy)
• History of carcinoma (excluding localized basal cell carcinoma removed or surgically treated with no recurrence
• History of thrombotic arterial disease (stroke, TIA, MI, angina) or deep vein thrombophlebitis
• History of CHF, cardiac arrhythmias, congential QT prolongation, and medications used to treat cardiac arrhythmias
• Gynecomastia > 2 cm, untreated
• Untreated gallbladder disease
• History of smoking greater than one ppd.