An apparel item comprising: a front panel having at least a posterior edge; a back panel having at least an anterior edge; a releasable coupling mechanism; a ventilation opening between the front panel and the back panel wherein the ventilation opening is configured to be opened or closed by partially uncoupling or coupling the front panel and the back panel via the releasable coupling mechanism to be in an open or closed configuration, respectively, wherein the ventilation opening begins slightly anterior to an armhole and terminates at a more posterior position at a bottom margin of the apparel item, wherein the ventilation opening is uncoupled at the bottom margin of the apparel item in the open configuration of the ventilation opening and the front panel and the back panel are secured together to form the superior margin of the ventilation opening; and an insert coupled to the front panel and the back panel, wherein the insert is configured to be exposed to the external environment through the ventilation opening when in the open configuration and wherein the insert comprises: a panel of material having an anterior edge, a posterior edge, a superior edge, and an inferior edge, at least a portion of the anterior edge of the insert (140, 150) is coupled to at least a portion of a posterior edge of the front panel, and at least a portion of the posterior edge of the insert is coupled to the back panel at a position posterior to an anterior edge of the back panel such that at least a portion of an inner-facing surface of the back panel is positioned adjacent to at least a portion of an outer-facing surface of the insert, wherein the releasable coupling mechanism releasably couples the posterior edge of the front panel and the anterior edge of the back panel. a front panel having at least a posterior edge; a back panel having at least an anterior edge; a releasable coupling mechanism; a ventilation opening between the front panel and the back panel wherein the ventilation opening is configured to be opened or closed by partially uncoupling or coupling the front panel and the back panel via the releasable coupling mechanism to be in an open or closed configuration, respectively, wherein the ventilation opening begins slightly anterior to an armhole and terminates at a more posterior position at a bottom margin of the apparel item, wherein the ventilation opening is uncoupled at the bottom margin of the apparel item in the open configuration of the ventilation opening and the front panel and the back panel are secured together to form the superior margin of the ventilation opening; and an insert coupled to the front panel and the back panel, wherein the insert is configured to be exposed to the external environment through the ventilation opening when in the open configuration and wherein the insert comprises: a panel of material having an anterior edge, a posterior edge, a superior edge, and an inferior edge, at least a portion of the anterior edge of the insert (140, 150) is coupled to at least a portion of a posterior edge of the front panel, and at least a portion of the posterior edge of the insert is coupled to the back panel at a position posterior to an anterior edge of the back panel such that at least a portion of an inner-facing surface of the back panel is positioned adjacent to at least a portion of an outer-facing surface of the insert, wherein the releasable coupling mechanism releasably couples the posterior edge of the front panel and the anterior edge of the back panel. a panel of material having an anterior edge, a posterior edge, a superior edge, and an inferior edge, at least a portion of the anterior edge of the insert (140, 150) is coupled to at least a portion of a posterior edge of the front panel, and at least a portion of the posterior edge of the insert is coupled to the back panel at a position posterior to an anterior edge of the back panel such that at least a portion of an inner-facing surface of the back panel is positioned adjacent to at least a portion of an outer-facing surface of the insert, wherein the releasable coupling mechanism releasably couples the posterior edge of the front panel and the anterior edge of the back panel.