In　recent　years,　eHealth　systems　based　on　the　Internet　of　Things　(IoT)　have　attracted　considerable　attention.　The　wireless　body　area　network　(WBAN)　is　an　essential　technology　of　eHealth　systems.　A　major　challenge　in　WBAN　is　the　design　of　the　medium　access　control　(MAC)　protocol,　which　plays　a　significant　role　in　avoiding　collisions,　enhancing　the　energy　efficiency,　maximizing　the　network　life,　and　improving　the　quality　of　service　(QoS)　as　well　as　the　quality　of　experience　(QoE).　In　this　study,　we　apply　the　mobile　edge　computing　(MEC)　network　architecture　to　an　eHealth　system　and　design　a　multi-channel　MAC　protocol　for　WBAN　based　on　the　Markov　decision　process　(MDP).　In　this　protocol,　the　channel　condition　and　the　reward　value　are　considered.　By　continuously　interacting　with　the　environment,　the　optimal　channel　resource　allocation　strategy　is　generated.　Simulation　results　indicate　that　the　proposed　WBAN　MAC　protocol　can　adaptively　assign　different　channels　to　the　sensor　nodes　for　data　transmission,　thereby　reducing　the　collision　rate,　decreasing　the　energy　consumption,　improving　the　channel　utilization,　and　enhancing　the　system　throughput　and　QoE.　©　2023　by　the　authors.