The boldfaced item can be replaced by the word in parenth...

“Taking a break in the workday is more than an indulgence, though:” lines 10-12 (therefore).

“ ‘Indeed, many people are wishing they could just peel themselves away,’” lines 20-21 (Nevertheless).

“Thus, invite a co-worker to take daily walks with you…” lines 22-23 (So).

“then commit to just one or two big breaks a week.” lines 33-34 (however).

“While most co-workers care less about your habits than you think they do,” lines 52-53 (Because).