metabolic equivalent unit (mets) formula

Posted by George on August 07, 1999 at 20:01:26PHi,                                                       In july I had a stress test on bruce protocol treadmill.Doctor gave me all test results except for the mets.These are the results of the treadmill bruce stress test.                                                     Event     Time     Speed     Grade     HR     BP          rest                                   99     144/80      stage 1   3:00     1.7       10        121    160/80      stage 2   3:00     2.5       12        136                stage 3   3:00     3.4       14        154    182/82      stage 4   3:00     4.2       16        168                stage 5   2:34     5.0       18        185                stop ex. 14.34                                            Interpretation: The patient exercised for 14.34 minutes on a standard Bruce protocol and stopped because of fatigue.The HR rose to 185 beats and the BP rose to 182/82.He denied any chest discomfort.There were no significant ST segment change.Summary 1.Negative exercise EKG 2.Excellent exercise capacity.                        According to the above stress test results, how many METS did I achieve? What is the formula for METS in stress testing?Thank you.George                                  By away I am 35 years old male weigh 166 pounds and 5'11 feet tall.PPHR WIDTH=75% SIZE=4 COLOR=#000090Posted by CCF CARDIO MD JMF on August 08, 1999 at 14:57:36PbrDear Gerge,pMETS or metabolic equivalents are estimated by the work load estimated at 14 minutes of a  standard bruce protocol in your case.  p1 MET is equivalent to 3.5 ml of oxygen per kilogram body weight per minute.  14 minutes into a bruce protocol, you are walking 5.0 mph on an 18 % grade this is the equivalent of 16 - 17 mets.  or about 60 ml/kg/min of oxygen consumption.  In general, we do not ask people to exercise at more than 5 mets for cardiovascular benefit.pSound like you're in great shape!  Keep up the good work!ppI hope this has been usefPosted by George on August 11, 1999 at 17:31:06

On which of these two tests did I (higher mets) do better heartwise? Also on the internet I found a formula for mets. It says "The mets used in the stress test is based on a formula utilizing the mean blood pressure multiplied by the heart rate".What do you think about this formula? Is this how mets are estimated? Using this formula how many mets would I have achieved?Thank you.George

Posted by CCF CARDIO MD JMF on August 17, 1999 at 13:43:35
Dear George,
Clinically, both tests are equivalent.  There is not much difference.  But to split hairs, the test in april had a better result....you walked longer and therefore utilized more mets.  As far as the formula, the HR/BP product is used to give an estimation of METS as is the time on a treadmill.  All of our formulas are estimations as i have previously mentioned to estimate METS.  We do not typically use this formula to estimate METS as it is prone to error.  In your case your METS based on this would be approximately 14 ( 185 (182)) which gives us a product that be scales is essentially 14