( ( ( The results ) ( of ( ( epidemiologic studies ) ( examining ( ( ( physical activity ) and ) ( cardiovascular risk ) ) ) ) ) ) ( ( have ( been ( ( taken ( as evidence ) ) ( that ( individuals ( should ( become fit ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS results)) (PP (IN of) (NP (NP (JJ epidemiologic) (NNS studies)) (VP (VBG examining) (NP (NP (JJ physical) (NN activity)) (CC and) (NP (JJ cardiovascular) (NN risk))))))) (VP (VBP have) (VP (VBN been) (VP (VBN taken) (PP (IN as) (NP (NN evidence))) (SBAR (IN that) (S (NP (NNS individuals)) (VP (MD should) (VP (VB become) (NP (NN fit))))))))) (. .)))
The results of epidemiologic studies examining physical activity and cardiovascular risk have been taken as evidence that individuals should become fit.
(ROOT (S (NP (NP (NN Smoking) (NN tobaccowould)) (ADJP (RBS most) (JJ likely))) (VP (VBP have) (NP (NP (DT a) (JJ negative) (NN impact)) (PP (IN on) (NP (NP (DT the) (NN ability)) (PP (IN of) (NP (DT an) (ADJP (JJ individual) (S (VP (TO to) (VP (VB succeed) (PP (IN at) (NP (JJ physical) (NNS activities))) (SBAR (IN because) (S (NP (PRP it)) (NP (PRP it)))))))) (NNP decreases) (NN stamina) (CC and) (JJ cardiovascular) (NN efficiency))))))) (. .)))
Smoking tobaccowould  most likely have a negative impact on the ability of an individual to succeed at physical activities because it it decreases stamina and cardiovascular efficiency.