In academic writing, many paragraphs or groups of paragraphs start with topic sentences, which are like mini-thesis statements. Topic sentences are idea indicators, or “signs” that help guide a reader along from idea to idea.
Topic sentences have a topic and an angle, just like thesis sentences. But the angle of topic sentences usually is smaller in range than that of the thesis sentence. Very often the topic remains the same from thesis to topic sentence, while the angle shifts as the writer brings in various types of ideas and research to support the angle in the thesis.
Look at this sample again; these are topic sentences created from the thesis sentence. The topic remains the same in all (regular exercise) and the overall angle remains the same (benefits). But the angle narrows and shifts slightly from topic sentence to topic sentence as the writer brings in different supporting ideas and research.
| Thesis Sentence | Topic | Angle |
| A regular exercise regime creates multiple benefits, both physical and emotional. | Regular exercise | Physical and emotional benefits |
| Topic Sentence | Topic | Angle |
| One physical benefit of having a regular exercise regime is longevity. Recent studies have shown that… | Regular exercise | Physical benefit of longevity |
| Exercise reduces heart and cholesterol rates when done at least three times per week… | Regular exercise | Physical benefit of reduced cholesterol |
| Another physical benefit of regular exercise is that it results in stronger heart and lungs… | Regular exercise | Physical benefit of stronger heart and lungs |
| People who exercise regularly have less trouble with sleep disorders… | Regular exercise | Physical benefit of less trouble sleeping |
| A benefit that spans the physical and emotional results of regular exercise is the release of endorphins, or substances produced by glands as a byproduct of exercise… | Regular exercise | Physical and emotional benefits of endorphins |
| In multiple studies, regular exercise has been shown to reduce stress… | Regular exercise | Emotional benefit of reduced stress |
| Because regular exercise often helps to slow the effects of aging and maintain a good body weight, people who exercise regularly experience the emotional benefits of good self-image and self-confidence in their looks… | Regular exercise | Emotional benefit of better self-image & confidence |
Realize that all paragraphs do not need topic sentences. Sometimes, you may need multiple paragraphs to help explain one topic sentence, because you have a lot of supporting information.